Morning Barrootz and Welcome to the Forum
Wow what a find, lucky man
You have started the process definitely change brake fluid (brake fluid is hydroscopic so absorbs moisture over time this can give spongy pedal or worse internal rust on brake parts) coolant again I would change as a matter of course. Transmission I would talk to a ZF specialist for advice as the miles are so low, I would also inspect the suspension bushes carefully they are rubber just like tyres they can perish with age.
For parts information www.realoem.com put the last 7 digits of your Vin in the search box it will bring up your model. Also look at www.newtis.info this one is a BMW Technical Information site the same information that Dealers use. I notice the steering wheel is on the wrong side so there is also a US site www.pelicanparts.com they have some great "How Too's" and good information with pictures.
ENJOY
Dave