This is going to be a long one.
The only abuse I see could happen with passing LR off to others is that a nonrebelling red could pass the LR to a rebelller therefore making it an illegal LR.
I could see a system being implemented to prevent rebellers from being gifted or given LR, or when there is 1 player, they can give LR to the last remaining RED, but if they choose to gift the LR, they cannot gift it to a BLU.
it would be better if during the zombie survival LR the blues are the medics and the reds are the engies as it makes more sense
That could be a possibility, but I of course never played Medics vs Engineers. I've only played zombie escape so idk. It also could depend for which side the engies and medics are on.
armoury would be a blu spawn so meds that spawn there would be invulnerable until they leave spawn
I think they should give some time for the engies to build defense from sentries and dispensers for at least 45 seconds before medics could leave their spawn, but i think they should give the meds another place to spawn in since medics would have an unfair advantage with ammo, especially with meds that have the crossbow, i'd rather give them a spawn further away from the armoury, especially in maps like Alkatraz which is a large map. But with them being invulnerable, it could lead to camping in spawn, which is a problem.
Also if a zombie survival LR was to be implemented you would have to make rules so the engineer team doesn't just build in hard to reach areas like obby
To prevent delaying, it would be a constant pain for the meds to reach the engies without sentry guns shooting them at farther ranges. Implementing rules could possibly help, maps like hopjb don't have these problems with obby, since engies don't nest in the map's obby minigame.
blu side teleports such as karts on mlcastle as the medics would have no chance if no rules were put in place.
That is true, thats why we have staff team as well.