As for stay and scream, assuming you can show up between 2-3 it’s entirely reasonable to expect to be able to do six different houses, provided you do them in this order:
1. Do the 3 2pm houses in any order, potentially repeating them if they are a walk on (Hellraiser has been the only house I’ve seen a walk on before 4pm.). You must complete them and be ready to enter house #4’s line at 4pm (when it opens, but the house won’t open till 5:15 so get comfortable)
2a. Get in line for Sinners at 4:00, after experiencing head to HR Blood’n’guts followed by invasion.
2b. Get in line for Ozzy and experience that, afterwards you have another choice to make:
I. Do Evil Dead Burn followed by Madlands
II. Do Cybergoria followed by Invasion.
I have successfully executed all these plans. You can really be over halfway done before the event begins.