Wow, this is a fun thread! I look forward to reading this as it grows.
We just went through the process last year and had to make all the same decisions that you are making now. I understand that you want everything to be perfect as you are dropping a huge nut on this project. First word of advice, ....don't stress too much.....it'll turn out beautiful in the end and you are going to love it.
My thoughts on your questions, plus some words of advice:
1. I'll start with words of advice on a topic you didn't bring up. Your happiness is going to depend on the contractor you hire. Please, please, please make sure you do a ton of due diligence in selecting your contractor. This not only means interviewing them and asking them all the relevant questions, but also doing site tours of other pools they have constructed as well as investigating/interviewing prior customers (those with postive and negative opinions). All pool contractors have negative opinions out there. Find them, investigate them and make sure you can live with the bad that might come with your contractor and don't believe all of the glitz and glory that the salesperson tosses your way. Our contractor (a major pool building company), builds and built for us a fantastic product (no complaints whatsoever); however, their customer service and timeliness absolutely SUCKS! We knew that going in so we were prepared for it. Also, as an attorney how has litigated against bad egg pool builders, make sure you get a good contract and pay specific attention to warranties. Its amazing what some pool builders will attempt to allege is "an act of God".
2. Pool Shape: While this is all personal preference, I agree that free form pools give that "resort feel" and in my opinion give your oasis more character. We went with a free form pool and I do not regret it. We are about 43' x 25' free form at the widest spots.
3. Tanning Ledge: This is one of those items that we went back and forth on over about a month and a half. We ultimately decided not to go that way based on the fact that we decided to spend the funds that would have been used on it. In the research I did though, I did find a ton of suggestions that you should make sure you have returns/bubblers in the ledge as the water tends not to circulate well in them if you don't. Also, the water in the ledge tends to stay much water than in other parts of the pool...generally.
4. Pool Depth: Like you, we do not have a diving board. We considered going with a shallower sports pool (for volleyball, etc) but ultimately went with an 8' deep end. The reasoning, ... we have children much the same age as yours, the youngest being a boy. Our concerns were when my son brings friends over when he becomes a teenager and they are being typical teenaged idiots, we didn't want them diving into a shallow pool thereby risking injury. Fingers remained crossed even with a deep end.
5. Pool Heater: Plain and simple....DO IT! We live in PA and our pool has been open since the third week of April. My son has been swimming every other day. I'll personally wait a little longer..LOL
6. Spa: We didn't do one simply because we have a hot tub not far from the back door of our house. We tend to use it only in the winter and the pool is much further (80 feet from the house). In PA, its brutal getting out of the hot tub to get in the house with it sitting right next to the door.....going from the pool in would be brutal. NC may be a lot different. A ton of people have them and they are awesome.
7. Retaining Wall/Raised Beam: We had similar issues with our terrain. We went retaining wall and created a much bigger deck area between the wall and the pool. Its the primary gathering area around the pool. Works well and built heavy duty landscape lighting into the wall. Looks awesome. BTW, if you are looking for very high quality landscape lighting.....check out Volt (
www.voltlighting.com). There stuff is awesome and very heavy duty. Did our entire lighting project thought them and could not be happier. You will pay for the quality though as the stuff has a pretty stiff price tag but we wanted something that wan't plastic that would last especially considering the money we've paid for the pool.
8. Inline/Salt Water: Salt water all the way. We went with the salt system when we put our in and it is the most user-friendly, low maintenance thing I've ever used and we have had multiple pools above and in-ground. Remember, a salt water pool is still a cholorine pool but the cholorine is just generated or added in a different way. The cool thing with the salt system is that the salt is broken down by the cell in the salt system which generates the chorine that sanitizes your pool. Once it does that, it reforms into salt and recycles. You have to add a bag or two of salt to your pool every year or, at most, a few times of year as a result of backwashing, etc but otherwise, you are not throwing harsh chemicals into your pool every other day. And, the water is so much softer. In my eyes, the salt system is a MUST over and above all of the other things above.
9. Another big tip: Before you lay your decking, spend a ton of time brainstorming. Think about all the things you may want around your pool (electric, water, speakers, etc, etc). Before any decking is laid, throw conduit (for electric, speaker wire, etc) or flexible water piping down so that it can be under the decking. That way, down the road you have a way to get utilities, etc to the opposite side of the pool. We laid conduit for a few outdoor GFI electrical outlets around the pool (two on our retaining wall. We laid conduit down for speaker wires to the four corners of our pool (so they are exposed just beyond the decking so that we could run a wired sound system (you may want to just go wireless or Bluetooth speaker or whatever as an alternative). Additionally, we poured a concrete pad as part of our decking big enough for a pool shed. In the shed I am partitioning off a section and adding a bathroom with a macerating toilet that pumps back into our septic system. We are trying to keep all of the water out of the house with our children and their friends. Next year, hoping to put up a pavilion with a stone fireplace and bar behind the pool. Hence the water line, etc. I guess my point is ................try as best as possible to envision now, what you might want to do later and get the underground stuff in. You'll thank yourself later.
Enjoy the process and don't be afraid to crack open a cold one as you feel the stress!