Seeing that his trial for money laundering is scheduled for September, sentencing on these charges or the money laundering charges probably won't happen until then anyway.

This is a serious question, I don't know how much power a Presidential pardon has.
Can one pardon cover multiple offenses/convictions?

Manafort's trial that's coming up next month could be considered more "serious" because it covers things that happened while he was working for the campaign. It could potentially implicate Trump or his family, and perhaps other campaign managers.

He can say it’s for only specific things, or makenit a blanket for any category of offenses or even all offenses, known or unknown.

Every single charge can be wiped out by a pardon, except for state charges.

The timing can be done when it’s lest harmful to him and the GOP.

If he refuses to talk and chooses to go to jail then his jail time would end when the Mueller investigation ends. Surely that would be sooner than any sentence he would get on his convictions, maybe a few years at best. Then he could take a job in one of Trump's companies and live a very nice life.

He can't escape justice because only Federal charges can be pardoned. It'll also start the progression to go after all others with states charges and no deals too.