Sorry for the delay I was in México! Sounds like your set for advice from what I can read.
As far as the well goes typically you won’t have spikes of high pressure as your pressure switch will shut off the pump when it reaches the set “cut off” pressure. If the pressure switch fails the pump won’t just blast unlimited water to your house, you won’t have any water.
If your going to temper the water I would run 1/2” pex from your manifold to a mixing valve and also 1/2” pex tee’d off of your hot line coming off the top of your water heater. Put shut off valves on both before the mixing valve. Then as stated earlier, adapt to 1/4” off the outlet of the mixing valve and send it to your sump.
Again as already stated, the less distance of pipe the hot and/or tempered water has to travel, the better it will retain its set temperature. I have since figured out the issue with my inkbird and still have no need to add hot water as my heaters do a fine job.
I still recommend adding filters too!