Congrats on the new pond. Sounds like a great situation for you to develop!

Here is a recent thread on walleye spawning that may answer a couple of your questions on that topic.

Walleye Spawning - PB thread

I believe we used to have one member that did have brook trout in his pond, but I haven't seen any recent posts (and can't recall the name).

We do have many people that do rainbow trout in their ponds. I believe they are more tolerant of the heat and low DO than brookies.

I think most of them ladder stock the rainbows every few years catch them after good growth and then re-start the cycle. One member was going to try making riffles and simulate a creek environment on his property to try spawning, but it was going to be a LOT of work. If you have access to heavy equipment and electricity on the property, then perhaps you can create trout runs and circulate water with a centrifugal pump (very efficient) during the spawning season.

I agree that your deep pond will almost certainly stratify - and have low oxygen water at the bottom as ewest says.

I wonder if you could set up a couple of moveable aeration diffusers to benefit your trout? Determine the depth of your thermocline in the summer and lower the diffuser a foot every week from the middle of July to the middle of August?

I hope you have great fun with your family enjoying your new pond!