I just can't think of a team who keeps 7 WRs. In fact, most keep 5 and only some keep 6. And on game day no way the Rams suit up more than 5 anyway.
I think the Rams will be among those who keep 6 and the 53 and I don't think the WR is hard to figure out.

Austin, Woods, Watkins, Kupp, Cooper, Reynolds

Austin, Kupp, and Cooper give you slot guys.

Woods, Watkins and Reynolds gives you WOs.

And of course the slot guys can do WO duties and vice versa.

Thomas's suspension has really cost him. Cooper is going to get a 4 game chance to cement himself in the lineup. If he is doing well and the chemistry is good, Thomas is not going to be given a chance. But.....the ol' injury issue can pop up at any time. And if we get an injury to any of those 6 then Thomas will wind up on the 53 after his suspension.