This is our first pool, and I want to make sure that our quote is fair and the equipment is good. All input will be greatly appreciated:

Pool and Spa 18X30
Perimeter 93
Area 491
Depth 3.6-5.6
2 Skimmers on Separate Lines
5 Return lines and directional fittings
4 Safety Main drains with Separate lines
Suction and Recirculation system piping size 2"
Over flow
Separate Cleaner Line
Auto Fill
Gas Line
System under pressure during construction
Spa 7' raised 6"
8 Jets
1 Reg Light for Spa
Coping is Flagstone
Water Feature is 2 manual sheer at 1' each
Peagravel 602 Sq feet (for Now going to see to add 200 more sq feet)
Gray Plaster
Filter 60FNS DE Pentair
Pump 4X60 Intelliflow Pentair
400,000 BTU Pentair
Platium Legend Truck Pentair
SWG
Easy touch 4
2 Reg Lights
Blower 1 1/2 HP Santanta
APEX 18,000 Gallons
I am pretty sure ( I hope) i have picked a good and reputable pool builder.

Welcome to TFP. Sounds like you are going to have a nice pool there.

Where does the overflow actually go? I found mine was piped about 2', then into a 4' length of drain pipe that went UP into the landscaping. Overflow water just seeped into the ground around the back side of the pool. I had it piped to the street, at great expense, after we bought the house.

Does this coping extend down to the waterline? If so, is it smooth flagstone or rough rock? Those 4 or 5" inches above the waterline can be where you get calcium stains and/or algae and rough rock is near impossible to clean.

I am somewhat suspicious of autofills on any pool here. It is just so easy to miss a leak and have the darn thing run and run. Take a look at what water rates will be going to soon and you will want to know for sure when you are adding water to the pool. Tap water adds a lot of TA to the pool which affects pH levels.

Also, mind the color of that grey plaster. It is quite surprising how quickly color converts to heat. My pool is just barely grey, and also gets some shade during the day, so it does not get too hot in the summer typically. Some years it has, some it has not. My neighbor has a darker color pool, also shallower, and it is warmer than mine even though it is more shady. You can fight hot pool water by adding fountains, but that means lots of aeration which means a climbing pH. SWG means climbing pH also. And our tap water is high TA so you are tending to high pH there also.