Trying to get all the basics covered and allow for "surprise" element also. (as much as possible anyway).
Big Blue 4.5x20 housings comment. Get genuine Pentair/Pentek, rather than knockoffs.
If an o-ring goes bad, mainly stretches so it will not fit back in, make sure you keep a spare. I have a list of compatible o-rings. Usually you can reuse. I lightly coat the o-ring with Molykote 111. A 5.3 ounce tube is a 2-lifetime supply.
Consider a bypass system. I have a ball valve in and out, and my emergency bypass would be to close those valves, and run a potable water hose between the drain valve at my pressure tank and a boiler drain valve following the backwashing and cartridge filters.
Also cartridge housings full of water are heavy to lift with outstretched arms. When tightening, I turn the housing CCW until I feel the click as the thread drops in. Then CW and you know you will not crossthread.
Note that the housings are not tapped for hanging from the bracket if you buy the housing separately. They expect you to use 5/16 x 1 inch lag bolts. I suggest stainless but not necessary.
Consider boiler drain valves between stages. You can attach a GHT pressure gauge to look for pressure drops. Some cartridge filters can mount pressure gauges.
Use polypropylene or polyester cartridges, and not cellulose, on non-chlorinated water. I like Pentek DGD-5005-20 polypropylene spun 50-5 micron.
After you do your plumbing, and develop your well, I suggest that you sanitize your well and plumbing.