No worries, there's no such thing as a dumb question!
I have to admit I'm not an expert on EMG pickups because they are famous for being rather clean / neutral / hi-fi sounding and I generally prefer something with a bit more personality / with a baked in 'flavour'.
Most EMG pickups are active and require a battery. However, they do also make passive pickups which themselves do not require a power source but are then usually mated to active tone circuitry -which again WILL require a power source.
If the below link works for you in the US, the EMG 35 set available from Thomann in Europe pictures the EMG 35 pickup along with an active tone circuit and battery etc.
https://www.thomann.de/it/emg_35dc_ebasstonabnehmer.htm
The EMG 35 size / dimensions have become an industry standard and many other companies produce something that will fit a body with that routing.
In my opinion, if you are looking at preserving / enhancing a Musicman type of sound with your next replacement pickup, EMG would not be my first choice and might be a bit generic / bland. Part of the Musicman sound is quite a heavy mid presence and I doubt EMGs would give you that. I hope any of this helps!
Peace,
Rob.