I appreciate your explanation of why you chose to use the term "monophysite". Unfortunately, that term has become perjorative through use; in fact, you are the only one I've spoken with online who seems to use it in a non-perjorative fashion. Because it does have that and other inaccurate connotations now, we have asked that it not be used here. You are invited to use "Oriental Orthodox", or, if you do not feel like using this term, "Non-Chalcedonian", a term most people have no problem with.
The non-Chalcedonian Churches feel no word used currently by those outside the fold is an accurate description of their faith; for them, the only accurate term is "Orthodox". Barring the full acceptance of that, however, they are content to use some of the other terms which are understood by others. This, perhaps, is why Abp. Tiran refers to his Church's position as "monophysite"; I have a suspicion that OO literature using that term is dated, and that modern authors do not use the term, a point I recently had to make to a professor who thought this use constituted the "self-identification" of these Churches as "monophysite".
Regarding your original questions, I am unaware of any OO theologians against reunion. There may be some, but I've never heard of them. I will ask around and see what I can find. When you asked about an OO equivalent to Maximus the Confessor, my first thought (before proceeding to your next sentence) was Severus of Antioch.