Asking because I couldn't find the exact answer in the forums or in their docs.

I bought the Orbx LA Helipads bundle this weekend and hoped that despite them not having RW identifiers, they might still show up. They do in the MS default flight planner but once you're airborne, I don't see any icons for them in FSTramp or the MS default VFR map.

You can certainly build a flight plan in the default planner and navigate to them that way, at least it's an option. But I was hoping not to have to do that for every single flight. Does Little NavMap show this type of scenery add-on? I'd imagine heliports are there but this bundle is all hospital and police helipads.

Yes

If it is bought from the MS market place it won't show up, as the LNM cannot read the encrypted files.

Nope, purchased from the Orbx site. I'll have to grab Little NavMap and have a look.

I built a helipad and a fictional airport using the SDK.  They show up in the World Menu and I can make a flight plan from there, but I can't find them in Little Nav Maps.

Which is kind of weird. Any other payware I buy shows up (as long as I remember to recompile the FSTramp scenery database before starting the sim).

LNM seems to be showing all the Orbx stuff.