Where to put whole house sediment filters
You ask some good questions, I would ask if the filter is rated to be on the output side of the pump. I normally install filters after the pump to reduce cavitation at the pump.
I install a string filter first after the pump to dampen the pump fluctuations some filters can be damaged so a string filter or porous ceramic that can be cleaned are my first.
then to the more sensitive charcoal and other filters. Keep in mind even on a city water system that is chlorinated that string filters can still start growing things if not changed out regularly a well water system with no treatment will need more frequent changes.
The other filters are usually based on the water quality and volume. 1 home we added a mechanical water meter inline that counted gallons as the owner requested this to get maximum usage of the filters without going beyond the MFG recommendations. Depending on water quality, well vs city the filter life varies.
the last thing I have installed is a UV treatment. I would caution don’t go with the cheapest system without verifying the lamp replacement cost. Some of the less expensive systems to purchase have 2-3x the cost of replacement so in some cases a more expensive UV purchase up front can be much cheaper by year 3.