I parboil my green pepper squares because it seems to help w/ the indigestion ...
That's not a big deal in my house, because there's round-the-clock hot water available on the counter - leftover from my loose leaf tea exploration some years ago ...
I don't like heated cherry tomatoes, personally, so I can't say much about them - other than that I stopped burning the roof of my mouth when I dropped the maters from my kebobs ...
As long as I pick the right sized onion, I can make a mixed kebobs that meet my spec ...
I really like having all three meats, personally ... I'll usually make some w/ boneless pork ribs and some with chicken thighs, in addition to steak ...
I took my wires out the other day, and I guess I'll have to make some, now, following the next grocery trip ...