Sounds like you have a handle on things.
I wouldn't worry about taking measure to get it eating again unless it starts to look unhealthy. You are correct BPs will fast and it's not uncommon for it to happen this time of year, a little early but its not like they keep a calendar.
Just keep doing what your doing and unless it looks undernourished or gets weak rely on the fact that it will eat when it is hungry.
If it is small/light the capacity for fasting is less but again don't worry until it shows signs of undernourishment.
However,
By not handling it now you are not damaging its comfort with being handled. Might take time to get used to it again but it wont decrease it's capacity for handling by not handling it now.
I wouldn't worry about blocking out the light from the enclosure with black paper, if it wants darkness it will go back into the hide.
I would also not switch over to live food unless you really need to get it eating again. At some point you will probably need to go from f/t mice to f/t rats and the switch will be much easier if it is only that and not live mice to f/t rats.
Hope this helps but like I said you seem to have a good handle on it.