Even if you don’t go with sps, I would agree with getting a powerhead, I find mine works so hard in moving food into the overflow so it is not rotting on the sand bed, even when the return is still pumping, turn the powerhead off and the difference is huge, some say a Random flow generator on the return is enough, could be but I would think you would be working much much harder for the same results.
the micro is a good option, I would stick with that, you need a load of little bits and bobs but big equipment for an aio is very simple, light, ato, heate, return and powerhead, going for sps I would get the best you can now, powerhead you have a few options, mp10 if you want to pay that much is a very good option, return you will be limited, some find the Sicce very quiet, I didn’t so went with the jecod dc 1200, light you have a few options again, my tank is LPS, no sps plans, I went with a Kessil a80, whilst it is rated for sps, may not be the best option, you could go Kessil a160, or the ai prime, or a few non top brand cheaper options out there but I haven’t looked into those, heater, again a few options but IMO you can’t go wrong with Eheim heaters.