1. I wouldn't remove com.mediatek.ims,com.mediatek.wfo.impl, Lenovo FC or,GBA service - you might brick the phone. Assemble test - maybe. It depends on what it does. (It's a pretty generic name.)
2. This isn't Windows, it's Android. Windows needs as much free RAM as it can get, Android needs
as little free RAM as it can have. (In Windows, if Windows needs used RAM, it has to swap one of the running programs to disk first, then kill it. Since all Android apps must keep their current state saved at all times, if Android needs more RAM, it just kills a background app. [Since it's in the background, you can't see it, so you won't know it's killed - and if you bring it back with Recents, it starts where it left off, so you'll still never know.])
Use root to uninstall apps you won't ever use and that the phone doesn't need (to save storage space), but don't worry about running out of RAM. You can't - at least not for a few years. (Eventually we'll see apps that are larger than the RAM in the phone -
that's running out of RAM. But 39.8MB being used? That's nothing. If it's even a 2GB phone, you should have over 1.5GB in use. (See
Multitasking the Android Way if you want an explanation of how Android works.)