en..in this scenario I would use a wsAP ac lite, or a gigabit port version when it comes
Lets say for some reason I do need to connect 4 devices over SFP, I'd get 4 x SPE to Base-T dongles. is it the BASE-T side goes to the device and the SPE side goes to one pair of UTP / STP cable that leads to the Mikrotik? if this is the case, how would the ethernet port on the Mikrotik know what to do with these SPE pairs? it would expect Pin 1, 2,3,6 with data and maybe the other 4 with power.
if the Base-T side goes to the mikrotik, you will need 4 port, that's probably not the case as you mentioned port splitting.
MTCNA MTCTCE UEWA