There are no BGL files in the 0202 scenery subfolder except the Microsoft-supplied ones with modified dates of August 2006.
Than it means the conflicting scenery is on another folder.
I cannot identify any source for those extraneous buildings other than the Microsoft default scenery.
As I've said, the default scenery cannot be the cause of this problem. You are being mislead thinking it is, because by disabling it the problem goes away, but the default scenery, alone, is not the cause.
Our AFCAD will disable every object from the default scenery. Provided, of course, KIAH is on an higher layer in the Scenery Library, which where the installer place it. If you moved it down, all bets are off...
Assuming KIAH is higher than any other layer in the scenery library, it's 100% sure the problem is caused by ANOTHER SCENERY, and NOT by the default one.
This scenery might have defined conflicting exclusion zones, making our exclusion zones ineffective so, the default buildings will pop-up, misleading you about the fact they are the problem, just because the buildings go away if you disable the default scenery.
In fact, you should NOT disable the default scenery, because KIAH is DESIGNED to work TOGETHER with it. If you disable the default scenery, you will likely lose all the instrumental approaches, and of course, you'll lose ALL the default airports that are included in that folder. And even if you disable *just* the .BGL belonging to KIAH, you will still lose several airports, since default AFCADs usually contain more than one airport.
So no, the default scenery is not the problem, and should NOT be disabled. You must be sure the KIAH area in the Scenery Library is on top of everything else (or at least, on top of every that MIGHT cause a problem), and you must be sure you don't have a conflicting scenery *everywhere*, not just in the default areas folders.