The answer for your letter form question is yes, but to some extent -if you ask from a popular science PoV- and no -if you mean the Qur'an as meant by scholars-!
But first we should make a clear distinction, which even many Muslims -due to lack of knowledge- don't correctly do.
Simply speaking the Qur'an القرآن is the orally transmitted word of God (Allah). It is not the book we hold in hands!
The book you hold in hands is a Moshaf (or Mushaf) المصحف (pronounced mos-haf) a written down copy of the Qur'an.
Now as we made this clear you will clearly conclude that the letters and their forms don't play any rule when it comes to the Qur'an, but could play an essential one in the Moshaf. Also anything but the orally transmitted word is not the Qur'an no matter if it is written in Arabic or Chinese ...
But as to the Moshaf there indeed are some rulings as the scholars are in consensus that the letters and words as written by the sahaba are canonical that's a main reason that still in a moshaf you may find for example:
الصلوة instead of الصلاة (prayer)
In best case a letter "alif" "ا" is only indicated in a moshaf as shown in this image:
The science dealing with this is the science of rasm al-Moshaf (the letters of the Moshaf). It is regarded as essential to keep the letters of the al-Moshaf al-Imam which has been made a standard by the caliph 'Othman ibn 'Affan. Scholars such as imam Malik and the scholars of his time would consider any addition (even the indication from above) as a addition to the original text which is not allowed. As for the writing style there are no rulings as far as the essential letters in general and words are kept in their original standard form (not style). Nowadays you will find only a few different writing or calligraphy styles in use.
So your statement:
"Your lams have unacceptably large flourishes, your mims have an extra small serif that has no precedent and just looks weird, and the loops on your qafs are 5% tighter than the defined benchmark standard as defined by the Standard Fatwa in Best Practices in Literacy. Your Qur'an is invalid.",
could be commented, by saying it doesn't play any role how you write the letters as long as they are readable. In a Moshaf nobody would use a hardly readable calligraphy as it would be a big sin if anybody read a letter wrongly and nobody would like to carry this burden. That's why Moshafs are almost written in a rather simple and readable handwriting.
Here some relevant posts: