@Dirk said I should run extra conduit and get a hose bib installed at the back end of the pool. These are awesome ideas I'm going to implement but I'm a little unsure about extra conduit for water. I get it for electrical, internet and a hose bib but not sure about water in general, from where to where and for what? I do have irrigation lines running already behind where the pool will be on the back of my property, but I wasn't sure if I needed more lines for the pool itself.
No, not for the pool. I meant a few runs of 1/2" or 3/4" PVC for irrigation or other uses. One for a hose bib somewhere near your pool, on the side of the pool opposite of the house, like in a planting bed or landscape area outside of the deck. Something to water plants or hose off the deck.
Additional lines (separate from the hose bib line) might be used for drip irrigation, or to fill a garden fountain, or for a sprinkler system. You might run a line from where your irrigation valves are to where your hose bib line comes up. Then just cap off each end. There if/when you need it. You probably don't need more than one line for a hose bib and one extra. You can throw some drip line into the trench, but that's a bit more susceptible to gnawing animals than schedule 40 (or 80) PVC.
If you've got irrigation covered, then you're good there. Though I added a few extra lines of irrigation in my yard so that I could separate out plant types. Some plans use zones. That's pretty easy. I went another way: one drip circuit for plants and shrubs in the ground, one for trees, one for all my potted plants, one for ground cover, one for just redwood trees. The thinking is that different types of plants need different watering schedules. You can achieve that with one line and different drip emitters, but I went the other way. Potted plants need more water more often than, say, shrubs in the ground. If my redwood trees look droopy, I can water them extra without overwatering my other plants. Like that. It's a bit overkill, but drip tubing is cheap. My landscaping runs all the way around the pool, all connected. So adding extra drip lines is relatively easy. The idea to add more PVC lines in the trenches really only applies if you have a landscaping area that is going to be orphaned from others once the deck goes in. That's the one that might need the extra buried lines.
Is there a way to just focus the solar heating on the integrated spa in summer so I don't have to fire up the gas heater as much?
I can't speak to Hayward gear. My Pentair controller can control both a gas heater (or heat pump) and a solar heater. I can set either pool or spa to use either heater exclusively, or both. My choices are "Heater", "Solar Pref" and "Solar Only." When in "Solar Pref" mode, the controller determines if solar can do the job, and then selects the appropriate source. So it would select solar on a warm, sunny day, and then switch to gas when the sun went down, whether that heat was intended for pool or spa. And all that can be scheduled. So I could have the solar heater pumping into the spa all afternoon, maintaining 85°, and then 1/2 hour before I got home from work, have the gas heater come on to 100°.
You might find out which Hayward controller is planned, then look up its owner manual online and see how Hayward handles this. I imagine it'll be similar, but now you know what to look for. I should mention that I don't have a spa, and I've never turned on my gas heater, so I don't have any real-world experience in how well that all works, I'm just sharing what I know about the capabilities of my controller.
Attached is the proposed light plan. I'm getting the spa and pool on different relays, but how does the layout look? The pool builder thought I should have another light in the deep end but that roughly points back towards the house. He says they are not that bright, Hayward color logic 320, but I want to make sure to have good coverage.
If coverage is an issue, I would put bigger lights where you have them plotted now, rather than point any back to the house or where you will likely be sitting out by the pool at night. Even if they are small lights. The rule-o-thumb is to just use your line of sight. Stand inside a window, or sit by the pool. If you can see the fixture (or where it's gong to be), you won't like looking into the light it'll emit at night.