Picasso triggerfish in a 75gallon?

I have a 75 gallon that is currently FW. However, I have had a 120g SW for over three years and finally feel comfortable with adding a second one. My first SW is FOWLR but I will be adding corals to it.

As I look at my 75g, I am seeing the idea of a Picasso Triggerfish and maybe two more fish.

Questions....

Do I need a protein skimmer or can I use the AC110s (2) on it now? I will get oneif necessary.
Would live rock be necessary? I like the looks of it and will probably get it, but would I need alot? Instead of 75#, could I get by with half of that?
What fish could I put with the PT? I have a silver scat in my 120g who I am afraid will eat some corals, so he may be moved. Would he work?

Oh, is the PT the most pet like SW fish out there? I have a 120g with a couple of Oscars (plus Jack Dempseys, Jewelfish, Firemouth) and am looking for the equivalent in SW.

Advice? Ideas?

 

I have a Bursa Trigger, a Panther Grouper, a Valentini Puffer, and a Lionfish with my PT (Humu-humu)...they all get along...i have a VERY over sized skimmer on my tank, because being pradators they are VERY messy eaters and poopers..lol;D