ADFs need room for movement, so I wouldn't put more than one in a tank of that size. The shrimp will be fine except that they will get eaten, eventually. Lots of hiding places and well fed frogs will help decrease the chance of shrimps-in-tummies.

If you do a google search, there are loads of care sheets to start you off, but here's one for now:
Untitled Document

I'm pretty sure the mainpage of that site, http://flippersnfins.yuku.com/, is a forum for ADF, so it might be worth poking around there for info, too.