I'm not understanding why you didn't remove the fuel rail and disconnect the fuel line before you removed the intake manifold. IMHO, you've made your life much more difficult when you did that. If you're worried about putting the last nut back (in your other thread), remove the fuel rail so you have access. Problem solved.
Stick a shop vac with a crevice tool into the intake runners on the block side when you reinstall the intake manifold just in case something fell in.
I think 10 posts ago it was recommended that you change the upper and lower o-rings to the injectors. If you decide to do that, my personal preference is the label the injectors so they go back in the same sequence or better yet, do them one-at-a-time so they don't get mixed up. Having said that, I'm sure others will say it doesn't matter where they go back in
I tried P21 per MrMCar's recommendation to clean the engine. Holy crap I was impressed.
Don't forget the missing vacuum hose to your vacuum canister. It goes from the canister to a port on your firewall. 3.5mm ID vacuum hose.