Right, we both agree that "it" in the second clause refers to the same "model that has the ability to re-roll its rolls To Hit". The presence of a semi-colon makes no difference.
Where it seems we are disagreeing is with the part in parenthesis. I interpret it as an example of ways a model might obtain a re-roll To Hit.
You seem to be interpreting it as an additional criteria that may be used to satisfy the conditions for gaining a re-roll on Gets Hot.
Yes the second clause uses the same "it" of "model with a re-roll". But since it is clear from the wording of BS6+ that you are not granted a re-roll until after you roll a 1, this is not one of the ways the same "it" may obtain a re-roll when firing weapons without a To Hit roll. Which makes it not an "it" at all!
Let's try an example:
If I have $5 (from work or ebay), I can buy a banana.
If I do not work and have $5, I can buy a banana.
These sentences make sense even though getting $5 from work is impossible in the second. Both refer to the same me in the exact same state: having $5. Just as both clauses are talking about a model being in the state of benefitting from re-rolls on rolls to hit.
Me not working eliminates one possible way of attaining $5 in the same way that having no To Hit roll eliminates BS6+ and Preferred Enemy as possible ways of attaining re-rolls on rolls of To Hit.
I hope I have shown that what's in the parenthesis is a description of possible ways to obtain a re-roll, and that it is context dependant. Even though we reference the same entity in the second clause, that doesn't mean what's in the parenthesis applies to this second scenario. How a model obtained re-rolls (which is in parenthesis) is separate from actually being in that state of having re-rolls. The pronoun "it" brings with it the latter (the state), but not the former (how it got to that state).