Certainly there isn't any requirement that you have a main drain or a wall suction. It simply cuts down on worries on those rare occasions when you can't empty the skimmer baskets for a couple of days. The automation system will protect the pump if the skimmers are both clogged, so the only worry is that you will stop getting chlorine added when that happens. That only matters if you will be away for several days.
I will get the pool up and running this year and see how it goes. I can always add a wall suction at a later date as it will be as difficult then as it is now since the liner is already in place. I will run an extra length of pipe and cap it at the pool for future use.
Eliminating the waterfall simplifies everything greatly. Now the only constraint is that you can't run the deck jets while you are heating the spa. That is a fairly reasonable compromise.
I can live with that.
2" pipe is enough for the spa, 2 1/2" is just better. Unless you are using very low flow jets, the flow rate will be pretty high and 2 1/2" will be more efficient. Still, 2" will work.
I am not sure what type of jets are in the spa. I will be setting the spa in the next couple days and will take a better look at them when I get it unpacked. To be honest my wife and I are not big fans of really high powered jets. She just likes to use the spa as a big bathtub that she can read a book in and keep an eye on the kids.
Actuators go into one of two different positions. There is no stoping at a third position unless you manually intervene. You can adjust exactly where those positions are, but you only get two.
Thanks, I understand that better now
On the return valve/actuator, there are three ways to plumb/set it up it and all three are common and all three work. The simplest setup is spa only and pool only. When the spill over is running then a lot of water is going over it and circulation in the pool is not so great. The next setup is spa only and mixed pool and spa spill over. That lets you run the spill over at a lower rate all the time without losing good circulation in the pool. Both of these setups use the plumbing the way you drew it and slightly different configurations of the return actuator.
The third, most complex, setup is spa only or pool only, and then a separate pipe with a separate valve that taps off before the main actuator and directs water to the spa spill over. This approach is more complex but it gives you extra control over both when the spa spill over runs and just how much water is flowing over it.
I was going to set it up as spa only and mixed pool and spa spill over but I will give more thought to the spa only or pool only option. I will draw up another diagram to post to make sure I have it figured out properly.
The 2 way diverter valve you have in your diagram before the pool returns split is essentially useless. When running in pool only mode you need that valve all the way open, and it doesn't serve any winterizing or servicing purpose.
I thought I could shut off the return jets to get more power to the step jets or the deck jets if needed. If it is not needed than I will eliminate it.
The check valve after the two pool skimmer lines merge is optional unless your equipment pad is well above the height of the pool water level.
The equipment pad is probably 2-3 feet higher than the water level. At what height does the check valve become necessary?
There are a couple of things you have done that are great, but most people leave out to save money. For example the check valve on the solar return is optional. Also, the 2 way diverter valves on may of the lines could be ball valves. In the other direction there are a couple of things you don't have that are optional but many people do have, like ball valves on the two solar lines to cut off the solar panels in case of leaks. Also a heater bypass as carlscan26 suggested. None of this is very important either way in my mind, small amounts of money.
I figured the diverter valves where only a little more money than the ball valves but would be a better valve in the long run. I will definitely be adding valves to the solar panel piping.
What is the benefit of a heater bypass?
I posed the question last year about solar panels and pump sizes and it was deemed that a 1 hp pump should get the water up there and prime the system. Once the system is primed the water flowing down acts like a siphon. At least that is what I understood.