The last-ever penny will be minted today in Philadelphia

Too early to say "ever", considering there has been no act of congress on this matter and the penny continues to be legal tender. The decision to stop minting it is a (legally debatable) executive order, and the next president or even the current one can change their mind about it tomorrow.

lets hope not. This is long overdue and should pose relatively little issue compared to most other recent questionable executive orders.

stop minting and stop accepting is commonly separated to allow adjustment. so likely a later president will just add the second phaseout step.

I agree it's time to follow Canada and the rest of the world but it needs to be done through congress, not executive orders. It needs to have a proper framework for migration and laws for how payments are rounded.