Vegetarian Substitue

Morning Star Farms makes a nice crumbled meat substitute. Their products are in the frozen food section.

Perhaps not a true substitute, but I really enjoy tempeh bacon for a savory, smoky, umami texture and flavor. You can find recipes on the web to season and make your own using a plain package of tempeh, or you can go the super easy route of buying something like "Fakin' Bacon" tempeh strips from Lightlife. It works well for pizza, sandwiches, and in quiche.

Smoked salt can add a salty/umami taste and might be good sprinkled onto the pizza or pasta. Not a direct replacement, but lends the smokey salty aspect.

I wouldn't call it a replacement, but I find smoked cheeses (liked smoked mozzarella) work well flavor wise when I omit prosciutto or pancetta.

I really enjoy the Morning Star Farms products. They are soy based and make a product called Griller Crumbles that’s great for pasta. Haven’t tried it on pizza but I’d think it would be good.
Love their Veggie and Black bean patties too.

It's not an exact replacement, but I've heard people make a thing called "carrot bacon" which might give you some good texture, saltiness and smokiness. Have been meaning to try it, but not yet done so.
See these recipes, which may interest you:
https://www.google.ca/search?q=carrot+bacon+recipe&oq=carrot+bacon+recipe&aqs=chrome..69i57j0l5.2832j0j7&sourceid=chrome&ie=UTF-8