Thanks for the extra picture. You have a nice space back there. Not tons of extra room but also not shoe-horned in when you are finished. Glad to hear you will be heating the pool for your comfort and ability to use your pool throughout the summer.
The Sunburst Honeylocust is a beautiful tree that provides great dappled sunlight below it - and the bonus of yellow leaves in the spring. Which is great because you can still grow grass and other things underneath. It is also fairly large in maturity, 35-40' wide. I only say this because I had one (past tense) and loved it. The leaves just disappear into the grass or mulch when they fall. The only problem is that, whether or not you realize it, they also fall all summer long (at least here mine did). Which meant that there were all these cool little green leaflets floating in my pool. Not so big of a deal if the skimmer would get them, but since they were so small, they stuck to the waterline tile with each wave's crest. I would absolutely not do anything with the tree until you see how it goes for a year or two, but I just had to share my experience with that specific tree which was about 35' (trunk to water's edge) away from the pool. I cut mine down after one year of pool ownership - and planted a Baby Blue Spruce in its place.
I'm going to make a suggestion of something that is expensive and I normally don't even suggest them to people. But in your case, there are many reasons why it could make sense for you. An automatic pool cover (autocover). My pricing is USD but they would run in the $10-15K range. There are several ways you can keep the cost down. And since your pool is a liner, that helps the cost in that the pit needed can be a plastic tub of sorts, versus a concrete pit. My reasons for (and against) suggesting an autocover are the following:
Pros:
1) Your pool will be heated (heated pools benefit greatly from being covered at night or when it is cool and/or breezy)
2) Covering and uncovering a pool with a bubble type cover is far less than something anyone enjoys - and therefore doesn't happen regularly as many attest to
3) You live in Toronto. Even summer nights can be cool.
4) You have a leaf/debris situation, even during the summer, that is conducive to having the pool covered.
5) Your late season leaf load sounds impressive. And with a heater, you will have the option to keep it open into/through September as the leaves fall. (Though you may not want to pay the bills to keep it heated that long.)
6) You have kids. How old? With young kids, an autocover is tremendous peace of mind. With older kids, it keeps them from swimming when you aren't home if needed.
7) You have a dog. Does he/she swim (we love dog pictures too!)? Since your pool doesn't have a separate fence around it, you may find yourself with a frequently wet pooch unless they listen real good.
8) Your pool is rectangular which is by far the best shape when using an autocover.
9) You only get one chance to install an autocover the right way (with the rails below the coping) which is during initial construction.
10) Peace of mind when you are not home (vacation).
11) Lower chemical usage (chlorine specifically if the pool is closed often). I strongly recommend a salt water chlorine generator (SWCG) for sanitizing your pool. So essentially that would need to run less, and therefore last longer and need to be replaced less frequently. Not a big cost savings item (small really) but worth mentioning. Regardless, SWCG's are the way to go.
Cons:
1) Expense, as mentioned. Honestly usually the dealbreaker. I had it on my non-negotiable list - so, no autocover - no pool.
2) Occasional maintenance is needed.
3) Cover needs replacing after 7-10 years.
4) You still need a winter spring loaded safety cover.
You may say nope and that's perfect. I just wanted to let you know you are an ideal candidate for one.
I'll think a little bit about your actual question of yard layout and give you my thoughts sometime soon. I got a little distracted above by trees and autocover as you can see.
LOL
for me!