4. What other things do I need to pay attention to?

If you do go with a new panel just be warned that the only safe way to
swap out the panel is to pull the meter off the pan to cut the power to
your panel. This is something that is only allowed by a licensed
electrician in my area, and probably yours too. Illegal for anyone not
licensed to do this. Maybe a call to your utility would help to see if
they would be willing to pull the meter for you if you go that way.
They could also advise you as to how big a new panel you could install
based on the size of your overhead or underground wires. Our utility
provided me with a list of approved meter pans that I could choose from
to get the job done. Went from a 60 amp Federal box to 200 amp box,
well worth it.