Substitute Romano cheese with Parmesan, if desired.
I've used regular pork before. It was wonderful too! I actually used Italian sausage for the first time when I realized I had the sausage but no pork on hand.
I've also used this exact meat mix to stuff zucchini before, put the entire thing in a slow cooker with homemade marinara... oh my!... after it had cooked for 4 hours I loaded an Italian cheese blend on top - it was sublime! Family dinner bliss - everyone ate til they were painfully stuffed.