Congrats on your new BMW! The waterpump/thermostat gig is very common. Wisdon indicates that these should be replaced with the upgraded waterpump (metal impeller instead of plastic) ASAP upon getting an E36. Trunk weatherstrip certainly seems within reason for a '96 (not ordinary, but if the person didn't keep the rubber cleaned/refreshed, this could very well happen...don't know what kind of summer/winter extremes you have which could adversely affect the rubber life).
On any used car you need to be aware of things that may be wearing out because of normal wear and tear...tires, brakes, battery, shocks. You also may want to take car to a BMW mechanic (not necessarily a dealer, as they tend to charge an arm and a leg for their work...albeit, they do a great job) and have them give the car a once-over along with a lube/oil change.
Lots 'o luck!
<span style='color:green'>1994 325i </span>- - - 75,000 mi.
No mods - - - very happy as is!
<span style='color:green'>1995 525i </span>- - - 154,000 mi.
No squeaks or rattles... unreal!