It's possible to use jQuery Mobile with WebForms, but it'll require some discipline to make sure you DON'T rely much on Postback style controls in your UI, but instead built a client centric UI.
Using MVC can be easier, simply because it is closer to the raw HTML without any HTML markup injection except what you put in the page. WIth WebForms you often have to worry about page hierarchy and control ID names as well as ViewState with postback vars. You can make it work without any of that, but at that point it's often just as easy to use MVC.
In the end it's all just HTML and you can create the HTML with just about any backend platform.
+++ Rick ---