Would this taste alright?

I’m planning on grilling up some kabobs on Friday for the first time. I have these ingredients:

Sirloin steak
Jumbo shrimp
Zucchini
Potato

1.) Should I use white, red, or sweet potato?

2.) Does the zucchini go with these ingredients? I’m not a veggie person and I’m trying these for the first time, as the typical tomatoes and onions are not my bag.

3.) How should I season this? I have a Lawry’s marinade that is supposed to be good for all meats/seafood and I also have teriyaki sauce. Do I marinade separately (like let the meat soak in it) or wait and season it all at once?

4.) What’s the best way to grill these so nothing is over- or undercooked?

Sorry for the stupid questions, but I’m a kabob virgin.