If I get an FN safety, I would have the bolt sleeve safety that I wouldn't be able to use due to the scope, and a trigger safety that I could use, right?
Well, you're only slightly confused.
A) Commercial FN Mauser rifle BOLT SLEEVES have no provision for a bolt safety - so, aftermarket triggers for FN rifles have a safety as part of the trigger group.
B) Military Mausers (98k) bolt sleeves DO have a bolt safety - so, aftermarket triggers for them have no safety as part of the trigger group.
C) Besides acting as a safety, Military Mausers use the bolt sleeve safety to hold the parts in situ for EZ bolt disassembly. Commercial FN's need help to disassemble the bolt for repair or maintainence.
SO......... IF you put the Timney/FN trigger, with side scope safety on your 98k - you will have one usable, day-to-day scope side safety on the trigger group, AND the original 98k bolt sleeve safety to use only for bolt disassembly.
IF you install the Timney/FN trigger, AND also don't want the extra, old, 98k, bolt sleeve safety - the entire bolt sleeve can be switched out for a safety-less FN-type sleeve, leaving you with a rifle that has a single trigger group scope-friendly side safety.
IF, on the other hand, you install the Timney trigger w/o a safety - the 98k bolt sleeve safety can be switched/converted to a low-scope type safety lever (quite common), leaving you with (again) a single scope-friendly safety, but atop the bolt sleeve ILO aside the trigger.
Either will work:
a low-scope, bolt-sleeve-mounted, Timney safety
- or -
a side safety on the Timney trigger.
It's your choice.
.