@3Dementia is right, I do need a second coffee.......
As to what would be planted; the challenge remains, its a proposed, strata park.
What that means, best case scenario is that all vegetation will be scraped off (and all soil) every few decades to redo membranes and make repairs.
Worst case is wholly inadequate soil depth, drainage issues etc etc. Above and beyond any normal, hostile urban conditions.
For that reason, I'd be disinclined to put Lindens or other trees that grow relatively slow and become very large with time. It means you'll never really see the full effect from them; and at the same time, their sheer weight and bulk (and water requirements) will likely accelerate maintenance issues and make them far more costly.
I'd be inclined, were I to put trees down in this scenario, to make use of fast-growing species that are likely to live about as long as the deck and not much longer.
Aspens would probably top my list; Birch and Balsam Poplar could be considered, but the former is not very urban tolerant and that would have to be considered (salt, car exhaust, in this case, for at least a little while, diesel, etc.)
One could include a smattering of others stuff for visual interest, especially in winter, but I'd be inclined to maximize shrubs and grasses for that.
Another thing to watch for here will be wind modelling. Many species, especially more Carolinean ones (we're at or slightly beyond the northern edge of their natural range) are particularly susceptible to high winds, especially in winter.