Maintenance on 2001 Mercury 125HP 2 stroke

I just bought a new boat and wanted to see what maintenance the experts on here would recommend I get done on the motor. It is a 2001 Mercury 2 stroke 125HP saltwater outboard. The good news is it has very low hours, I purchased it from the original owner and he had all the original purchase paperwork to prove he had owned it since 2002. The bad news it has been driven very little, The seller lived on a lake but is 73 years old and said he has only taken it out a handful of times the last few years. It has always been stored inside a metal building on his property and he said he has never had the boat in saltwater.

He also said it sat without being used for a few years after he had an accident but around 2013 (after he got better) he claimed the entire motor had been gone thru and that he has had no issue with it starting and running since then.

So it is working fine now but with no records of maintenance in 4-5 years what should I get done?

No one has suggestions for maintenance items I should do (or more likely pay someone to do) on the motor I'm buying?

Change the water pump impeller and lower unit oil. Fairly easy to do if you are mechanically inclined.