Max surface temp of 71 F.? That's still about six degrees higher than I would want it. Any possibility of some cold water inflow as in a well or something? Might not take that much to drop the pond a few degrees during the hottest par of the summer.
Or some serious aeration on the surface when temps drop during the night into the 50's during the warmest part of the year could pull you through with trout.
Do you have access to brown trout? They would be able to tolerate marginal water temps better than rainbow and especially brooks.
No experience with hypolimentic aeration, but it sounds good on paper. Bascially you are adding D.O. but not enough to break stratification.
When you have all the information you need and you're still scratching your head on if it will work, the best thing is to just get some trout and see if they make it. I would put larger fish in like 12 to 14 inches so that if they don't make it there won't be any other factors to confuse you. It's also possible you may lose some, but some will make it. If you do plant some and you see a few morts don't give up right away. Some fish are hardier than others.
