Is my mid-2012 MBP overheating?

The temps are about normal, some are on the high side but not by much.

I would guess your system is likely dusty inside. A can of can'ed air a small soft paint brush to scrub the fan blades and heat sink fins is all you'll need here after popping the bottom cover following this IFIXIT guide: {Substituição da estrutura inferior do MacBook Pro 15" com tela Retina de meados de 2012|MacBook Pro 15" Retina Display Mid 2012 Lower Case Replacement]. Just be careful here as you don't want to damage your system follow good ESD protection practices as in the winter with the dry air it's a system killer.

As far as the trackpad: Have you tried clean it with some isopropyl alcohol? Slightly dampen a paper towel and tried just wiping it down, The trackpad surface is glass so I doubt you damaged it just from regular use. They do get dirty from the skin oils and other junk that gets onto them. Replacing the trackpad is not something I would recommend you try in this series as its a very big job. Best to bring your system into an Apple Store and let them do it if its that far gone.