Long story short, I ended up not going the planted route. Building planted/bioactive enclosures for heavy-bodied reptiles is hard -- exponentially harder than doing so for dart frogs, small lizards, and small snakes -- and there's a good chance you'll wind up spending more time on the garden more than the reptile should you pursue one. I decided it was more than I could chew as a novice keeper. I'd highly recommend reading Bio-Activity and the Theory of Wild Re-Creation (one of the Arcadia Reptile books) if you haven't already. It lays out the important considerations one should make when designing planted/bioactive enclosures very well, and should be mandatory reading for anyone pursuing a bioactive project (IMO).

In your case, you may be better off using artificial plants in the areas your boa will heavily traffic (ie. the floor, their perches) and only planting your live plants on the walls. They're much less likely to be trampled there. You may be able to circumvent the LED heat issue if you find a way to install screens in the ceiling of your enclosure and externally mount them. That way, the heat from the LEDs can dissipate into the room instead of the enclosure. It would also bring the added benefit of protecting your boa from burning themselves on the lights and increasing ventilation.

Good luck! Even if you wind up using more artificial plants versus real ones, I think you have a very cool looking naturalistic enclosure in the works here.