Hi Scott. Are you limited by space? The pool will be pretty small unless you only have a couple of people using it. I'm a family of 5 and my 16 x 32 is as small as I'd go for 5 at a time. Put Pentair or Jandy valves in the contract for sure. Some builders use simple ball valves that don't last over the long-haul (these are the shut off valves at the equipment pad just before the equipment). If you are staying at 4.5' I personally would go with an above ground pool. You could get the pool at 54" and a small deck for it for a fraction of the cost. I wouldn't go 3.5'. If you don't want it deeper than 4.5' I'd make the entire pool that depth of 4.5'. Get a salt water chlorine generator too. I'd skip the color lights and go old school and get a white light. They are more reliable and much cheaper (the halogen bulbs). My Jandy led lights failed after 4 seasons. Also the 420 filter is way, way overkill for a <9k gallon pool. My pool is about 20-21k and it's way more than enough. My .02 is to let the builders quote the very large filter and then negotiate down. These are personal decisions so do what your gut tells you to do. Either way you'll love it!
-Chris
I almost posted exactly all of this. I went 6' deep and probably wouldn't use the pool without it being that deep. 4.5' isn't adequate for adults. I agree with the light. I regret doing the fancy expensive light as cool as it is because even though we swim mostly at night, it's not on enough to ever make up the cost in electricity. You can get LED bulbs to replace the halogen ones in the fixture but if you buy a expensive light, you can only replace it with an expensive light later on (or a same brand Halogen fixture which is what I will do. I will go farther and say that when I replace it I'll also convert it to 12V for extra safety).
My pool if 14Kgal m/l... if it were any smaller I don't think it would have worked. It's big for 2 people, but right on the edge for all 6 of us. I think I picked a good size.
My filter is way oversized for my pool as well. If it's a cartridge filter that is a good thing because you can clean it less frequently. If it's sand or DE it probably doesn't matter, so the smaller sized one would be better. Our HOA required the cartridge type...
I agree with Jandy valves. My builder is a Hayward shop... except for the valves... So I give them credit for that. Dump the inline chlorinator and either pay up front for the matching SWCG or install one yourself at the end of the first year if you don't care about automation. I am HAPPY I didn't get automation. More expensive stuff to break. I have my light on an Alexa switch and that's good enough. PB's love inline chlorinators. You can buy one for about $30 and install them in 10 minutes, or you can pay $500 for them to do it for you. And they add CYA like crazy...
I'd spend my money in a bigger pool and less toys like automation. You can always add toys later yourself if you are handy.
There is no such thing as a pure saltwater pool The salt is the source of chlorine that is released by electrolysis. Otherwise the oceans would be sterile at the ten times higher salt concentration then a typical SWCG uses. Obviously that is not the case. Some people add salt without a SWCG because frankly the water is more buffered like human tears and other fluids and it just feels better. But if they do that they are still adding chlorine.
As for your space restrictions. You might be able to get waivers for some of that stuff with an engineer's stamp. Can you pay the utilities to bury the lines? Is that an option? Yeah that's a couple of grand but it's a good idea too. (And you probably could then do an above ground if you wanted.) Having water near the foundation of a house can be mitigated with more money... I am assuming you are on a slab in Houston as it's a "Wet" area prone to flooding IIRC. You can have something engineered for that too. It's all money. The other option would be to consider to move and start over in a new house. That's always valid. Not building the pool at this time is always and option too.
Good luck. Go as big and deep as you can, especially if you don't have small children.