While the battery is glued down with adhesive, you can just soak it in some 91-99% isopropyl and that adhesive dissolves quite rapidly and the battery can be pulled right out. I had no issues doing this on my 2016.
I just finished completely rebuilding a 2008 and 2010 macbook pro. The older ones are quite serviceable. This round, the speaker surrounds had cracked causing buzzing audio or no audio. I managed to ebay brand new speaker replacements and got them installed. I cleaned everything and re-pasted the CPU/GPU while I was in there as well. They are on El Capitan and High Sierra, but can be patched to be upgraded to Mojave if I wish. Currently running a LTS version of Firefox as my browser.
I just finally decomm'd some supermicro X9 boards that required me to keep a copy of firefox portable and either use Java 7, or configure out some security settings on java 8, but they weren't that hard to maintain/admin.
Your stuff seems like it's at least a gen newer, and probably really isn't that difficult to admin at the BMC level.