All Praise to Allah Subhanahu wa Taala and blessings of Him be on Prophet Muhammad peace be upon him His family and companions,
There are some very clear ahadith showing that Rasulullah salAllahu alayhi wasallam had no shadow but some scholars keep different opinion on it ,Majority of very prominent scholars ,Muhaddith and Mufassir including Jalaluddin Suyuti (Ra) are of this opinion that Prophet Muhammad peace be upon him had no shadow.
"The shadow of the Prophet could not be seen in the brightness of the
sun , nor in moon light".(Hakim Tirmidhi)
Narrates from Sayyidina Uthman ibn Affan Imam Nasafi , that he (Uthman
bin affan) said to the Prophet "Allah Almighty does not let your
shadow fall on the ground, so that no foot of man can fall on it".(Tafseeer Madarik)
It is mentioned in very Famous book كتاب الشفاء بتعريف حقوق المصطفى That Rasulullah salAllahu alayhi wasallam had no shadow in the brightness of sun or in moonlight because he was light(Noor)"
Now as you stated that he is eternal, that he wasn't a human or bashar as some claimed so its misunderstood because no muslim claims this because the belief of Ahlus Sunnati wal Jamah is that Rasulullah salAllahu alayhi wasallam is offcourse human as these prophets were not selected among Jinn or angels but in humanform so that they could convey the message of the Lord Subhanahu wa taala.But he peace be upon him was not like an ordinary human we do not receive revelation like him, Our sayings are not the hadith and part of shariah like him ,Allah swt did not order in Quran to follow ordinary man like us but to follow him so that we would be guided.
He who obeys the Messenger, has indeed obeyed Allah..(Quran 4:80)
قَدْ جَاءَكُم مِّنَ اللَّـهِ نُورٌ وَكِتَابٌ مُّبِينٌ ﴿١٥﴾ There has
come to you from Allah a light and a clear Book.(Quran 5:15)
Many Mufassir have explained that the "Noor light" here refers to Rasulullah peace be upon him.Also see this for more.
This hadith is mentioned in some tafaseer that Narrated from Qataddah “I was created before every one and I came at the end of all the Prophets.”(Tabari,Ibn Kathir Qurtabi)
So He was created which rejects the idea of eternity and I havent heard it before that claiming him to be eternal which means "no beginning no end" as only Allah Swt is eternal and the rest are "Haadith"(which was not existed and then came into an existence).
Now regarding the other things you quoted are Mustahabat and sunnah of the companions (may Allah swt be pleased with them)like arranging a gathering to Thank our Rabb for we are blessed to be born as His Ummati.
It was narrated that Abu Sa'eed Al-Khudri said: "Mu'awiyah, (may Allah
be pleased with him,) said: 'The Messenger of Allah [SAW] went out to
a circle - meaning, of his Companions - and said: 'What are you
doing?' They said: 'We have come together to pray to Allah and praise
Him for guiding us to His religion, and blessing us with you.' He
said: 'I ask you, by Allah, is that the only reason?' They said: 'By
Allah, we have not come together for any other reason.' He said: 'I am
not asking you to swear to an oath because of any suspicion; rather
Jibril came to me and told me that Allah, the Mighty and Sublime, is
boasting of you to the angels.'"(Nasai)
For some other belief you quoted see this hadith when the companion asked that how we would be able to send salawat/Durud after the death,
It was narrated from Abu Darda’ that the Messenger of Allah (ﷺ) said:
“Send a great deal of blessing upon me on Fridays, for it is witnessed
by the angels. No one sends blessing upon me but his blessing will be
presented to me, until he finishes them.” A man said: “Even after
death?” He said: “Even after death, for Allah has forbidden the earth
to consume the bodies of the Prophets, so the Prophet of Allah is
alive and receives provision.’”(Ibn Majah)
Also see this video that his blessed hairs were shown in a museum of Dubai and it grows ,Rasulullah peace be upon him distributed his blessed hairs to his companions,
Another narration is: After the Messenger of Allah (ﷺ) had thrown pebbles at Jamrah and sacrificed an animal, he turned the right side of his head towards the barber who shaved it for him. Then he called Abu Talhah Ansari (May Allah be pleased with him) and gave his hair to him. Then he turned his head to the left side and asked the barber to shave it. He gave the hair to Abu Talhah and told him, "Distribute it among the people."(Riyad as salihin)
Most importantly this hadith shows that what was the way of companions regarding the behaviour towards him and how they show reverence and seek blessings from his blessed spittle ,and struggle to attain his remaining water he used in ablution,
'Urwa then started looking at the Companions of the Prophet. By Allah, whenever Allah's Messenger (ﷺ) spat, the spittle would fall in the hand of one of them (i.e. the Prophet's companions) who would rub it on his face and skin; if he ordered them they would carry his orders immediately; if he performed ablution, they would struggle to take the remaining water; and when they spoke to him, they would lower their voices and would not look at his face constantly out of respect. `Urwa returned to his people and said, "O people! By Allah, I have been to the kings and to Caesar, Khosrau and An- Najashi, yet I have never seen any of them respected by his courtiers as much as Muhammad is respected by his companions. By Allah, if he spat, the spittle would fall in the hand of one of them (i.e. the Prophet's companions) who would rub it on his face and skin; if he ordered them, they would carry out his order immediately; if he performed ablution, they would struggle to take the remaining water; and when they spoke, they would lower their voices and would not look at his face constantly out of respect."(Bukhari)
Thus this is the aqeedah kept by Ahlus Sunnah wal Jamah and their Fiqhi Imams (Abu Hanifa ,Imam Shafai ,Imam Malik,Ahmed bin Hanbal) as well.
In your last paragraph you have quoted some ayahs which says that prophets are "bashar" like us so let see the meaning of it.Bashar is from basharah which means the outer side of the skin so Insan is also called as bashar because their skin is exposed unlike animals as outer skin of animals are covered with hairs etc so In Quran when Allah swt has used the term bashar it specifically related to the appearance of Insan usually which means that yes prophets are created in that form in Human form.
Now here in that ayah we see Allah Swt asked Rasulullah salAllahu alayhi wasallam to let kuffar know and address them that Allah swt has chosen him among the people so that they do not consider him like nasara or jews considered Prophet as the Son of God or Part of uloohiat but when Rasulullah peace be on him was addressing to His companions he said that "I am not like you".
'Aishah (May Allah bepleased with her) reported: The Prophet (ﷺ)
prohibited his Companions out of mercy for them, from observing
continuous fasting without a break. They said: "But you observe fast
continuously". He replied, "I am not like you. I spend the night while
my Rubb provides me with food and drink". [Al-Bukhari and Muslim]
So there is a difference when addressing to the mushrikeen he said that I am a prophet and a human like you but when addressing to the Muslims and blessed companions he mentioned I am not like you (which does not mean that he was not a human).
Just think that a very long time worshipper of God and the true believer of oneness of God i.e "Shaytan"who was regarded as the preacher of angels was not able to bear the honour given by Allah swt to Prophet Adam peace be upon him so he did not bow in front of him out of jealousy and pride which led him to become the cursed one then.So we need to show respect and love to Our beloved Prophet Muhammad peace be upon him see so we are not following the way of shaytan See this.
So how the kid would be able to love and respect his parents when he is not taught the Iman which is to love and respect the Rasulullah salAllahu alayhi wasallam most of all.
The Prophet (ﷺ) said "None of you will have faith till he loves me more than his father, his children and all mankind."(Bukhari)
Allah Swt and His Messenger knows best.