for the conveyor thing it could be good but it might need more explaining , and for the hallucinations welp i don't remember seeing any from CTI , if you mean the moment when he teleports around it wouldn't do much unless it was in the hallways since blocking the view for a bit isn't that bad if you know where he is
I think I will go with placing buildings, 2 to be exact, the sentry, and the dispenser. (This is just an edited your idea btw) He can place sentries in the halls, which shoot slowly and cant die (for technical reasons) but they get removed if he dies. Dispensers give him a very small amount of health regen (Because that's enemy medic's thing) but boost his firerate briefly upon entering a hallway (to avoid his boost just dont enter the hallway immediately.) When I wrote the previous comments I forgot I actually did know a way to add buildings sry for the mistake!
I dont know if his rework will be a part of the next update since this one is already quite ambitious but ill try to squeeze in the red engi rework! Any other feedback is much appreciated!
To do with the intel task.. Ill make it 3 times slower before 6 am, otherwise it would just be extending the night. so if players have a period of time free, they can make the night a little shorter.
maybe give him a revolver and a the Tribalman's Shiv (one of his melee's), the revolver can shoot 6 times before getting a cooldown and the melee makes him able to attack when they get close
he also has 1 extra ennemy stage before the hall attack triggers so he can use the melee (that or make it so the current last phase is the one you can melee on)
the revolver can crit with a headshot on the last shot and if you land the crit the reload get's shortened
BUT it is at the cost of of increasing the ennemy tension by 20
basically a revolver that can do some good damage and do a crit in a pinch at the cost of reload time and tension and a melee for really bad moment's (also the reload system could be made in a way like for the railgun from engineer exept it slows the firerate to almost nothing after 6 shots instead of changing due to hp)