For the first question, there’s a distinction between state and federal crimes, things like shoplifting are usually state level crimes, if you do something like counterfeiting or crossing state lines while doing a criminal activity that’s often federal. The president can only pardon federal crimes, they can’t pardon a state crime (a year or two ago Biden pardoned federal weed offenses but that affected almost nobody because most people jailed for weed are at the state level which he couldn’t pardon). Trump’s charges in New York are state level and he can’t pardon those.

Whether or not Trump can pardon himself for federal offenses (like the case in Florida that’s been killed by that Trump-appointed judge) is yet untested (Nixon resigned and was pardoned by his successor to avoid this exact question), and it’d likely go to the Supreme Court… so they’d probably let him pardon himself.

I’m going to pass on the second question because I think he could actually be president from jail but I don’t know for sure. I’m not a lawyer, lol. Didn’t legal eagle do some videos about this?