well the egr valve stays with the egr tube so that has to come off, I would remove the iac to prevent damaging that and if you are going to clean the lim/uim might as well take the tb off to clean the egr passages and the tb itself
I would just tape it off and let it soak, also you need to get in there with a brush as just soaking it will not remove much
now if you want to leave the tb and iac on the uim when you remove it from the car that is a good idea
