Advice from Dumb Friends League

I just got off the phone with an animal behavior specialist at Dumb Friends League and here is what I'm going to do:

1-Go back to square one with introductions
2-Rub a towel on the other cat(s) and put it under their food bowl so they'll associate something good (eating) with the other cat
3-Have them change rooms for a few hours, every few days
4-Gradually crack open doors so they can see and smell each other but not touch or feel threatened/threaten others
5-Talk to vet about anti-anxiety medications (we don't want to use medicine at this point in time... so)
6-Over the counter remedies (Feliway and a few other options I'll post more about later when I get the literature in my email)
7-More perching space (they can share space but don't want to be in each other's grill)
8-The shared litterbox is good... I'm going to add a shared drinking station
9-***Clicker training *** (She said they have had really good feedback on cat clicker training - seriously.  She said it's worth the effort and time from the feedback she's gotten.  Apparently it's not just for dogs.)

I was also told (and I already knew this) that with my sister-in-law's cat and dog coming in a few weeks, "Things will get worse before they get better."  However, since at one point many, many months ago we did have Vante, Amelia & Callie Mae integrated, then there is hope that we can make it work again.  It'll just take more effort.  They're worth it though... and I'll keep everybody posted on their progress.