The SEEDBAG COMBI thing was a good find, I fixed that. SEEDBAG was not included in THE DROPPER when modes changed, so floated forever.
I suspect the KEY issue is EasyRPG Player, because it "looks" fine and works in-engine here. It's pretty important to be able to pick it up. I'm not sure what I'd suggest for that beyond sort of un-hiding it (maybe EasyRPG doesn't like the layers you find the KEY behind?), but having so "grabbed" the KEY, does it let you open the side gates anyways? Picking up the KEY is a SWITCH as opposed to an actual ITEM, so it might actually be turning on that you "have" the key in your hands even if it isn't floating above you visually.
The DRAIN SPIDERS are a good point, and upon reviewing them they are in fact the "old" SPIDER script which as you experienced knock the GLAIVE from your hands on contact unless you have the RED RUBBER GLOVES equipped.
The updated SPIDER script I've put into them lets you hit them once with the GLAIVE and then if you lack RED RUBBER GLOVES, they disarm you.
Thank-you for all the suggestions.