I do not know any Hadith or Ahadeeth that supports such a combination (and most of the things in it) for when going to sleep. There are though prescribed Ad'iyah and verses for the night time, most of which I do not find in the above quoted section in your question, for example I do not see anywhere where it says to say Surat Al Ikhlas and Al Ma'udhatain three times when you go to bed and when you wake up, and that is of the sunnah!
So I am saying there are prescribed things for the night, for more information see pages 28-30 of this book, you may also wish to see the Ahadeeth for their authenticity, but the authors of the book tried to make sure that all the things entered are authentic. Furthermore you may check Riyaddussaliheen by Imam Annawawi (you can find a copy on sunnah.com).
Is it right for scholars/raqis/imaams to create new quranic ayat combinations like this?
No, no one has the right to make any new combinations not found in the Quran and Sunnah and say do this at this time and this will happen. for example it is not ok to come and say do this so many times and this will happen. Or read this so many times when you go to sleep, and there is no sunnah to support it. No one has the authority to do such thing. Furthermore if the medicine and the Adhkar and Ad'iyah, and verses and Ruqa from the Sunnah are studied alone, one will have enough to occupy him/her self that there is no need to invent new things/combinations.
As for what you have quoted:
(1) Istighfar 3x
The best supplication for seeking forgiveness (Syed-ul- Istighfar) is
اللهم أنت ربي، لا إله إلا أنت ، خلقتني وأنا عبدك، وأنا على عهدك ووعدك
ما استطعت أعوذ بك من شر ما صنعت أبوء لك بنعمتك علي، وأبوء بذنبي، فاغفر
لي فإنه لا يغفر الذنوب إلا أنت
O Allah! You are my Rabb. There is no true god except You. You have
created me, and I am Your slave, and I hold to Your Covenant as far as
I can. I seek refuge in You from the evil of what I have done. I
acknowledge the favors that You have bestowed upon me, and I confess
my sins. Pardon me, for none but You has the power to pardon
He who supplicates in these terms during the day with firm belief
in it and dies on the same day (before the evening), he will be one of
the dwellers of Jannah; and if anyone supplicates in these terms
during the night with firm belief in it and dies before the morning,
he will be one of the dwellers of Jannah
(2) Fatihah 1x
It is known that reading the Quran has blessings and deeds, and with each letter you get good deeds. But I do not know any Hadith pointing to that reading the Surat is part of what you do before you go to sleep.
(3) Ayat Qursi 1x
This is known, and there is a Hadith in Saheeh Bukari to support it.
(4) Al-Imran: 26-27 1x
I do not know a Hadith saying to do this when going to sleep, but it is narrated in Saheeh Bukari that when waking up to pray the Prophet (peace and blessings be upon him) used to recite the last ten verses of Surat Al Imran.
(5) A-Baqarah: 285-286 1x
It is narrated in Saheeh Bukari that those who recite that last two Ayahs of Surat Al Baqarah they will be enough for him for that night.
(6) Salawat 21x
This I do not know, whether there is anything to support it, and Allah A'lam. There are blessings in doing Salat on him, but i do not know anything about it being part of what to do when going to sleep.
(7) Al-Jinn: 1-5 21x
Again like Surat Al Fatihah, there is blessings and deeds for reading Quran. I do not know any Hadith supporting it, but it is ok to read it now and then not for the intention of it being sunnah but for gaining good deeds and blessings, but not do it all the time so that it does not become as if it is sunnah, See this for more information.
(8) Al-Kauthar 11x
Again like I said about Fatihah. I do not know any hadith supporting doing this at night, especially 11 times.
I do not know about this.
Lastly I apologize for the answer's length, and I ask Allah for forgiveness of any mistakes, and that he guides us all.