For the Buffalo Tempeh:
If making the ranch from scratch is not your forte, you can use about a cup of your favorite vegan-mayo and add to it the lemon, herbs, and seasonings to taste.
For the pizza crust, I do not currently have a recipe that is perfected to share with you. Once I do, I will make a separate post and link back to it. There are plenty of vegan pizza recipes out there, but for convenience, Trader Joe's, Whole Foods, and Wegmans all carry vegan crusts. If you don't have access to any of those stores, Pillsbury has a pizza crust that is 'accidentally' vegan.
For the sauce on the pizza, I find that most people simply use additional hot sauce. I, personally, find that a little dry and prefer a pizza with more sauce, so I like to use a bit of tomato paste mixed with hot sauce. If you like a saucy pizza, I would recommend doing this for yours.