Mantua has pretty good ice; been up to 5" before this present cold snap. I'm guessing it's going to be well over 6" by this weekend. Bluegill fishing there has been fair to excellent depending on the day. Plenty of rainbows to keep you busy too. East side has been better for me; 10-14 FOW.
Causey capped and people have been fishing it successfully. I haven't personally been there but plan on it probably tomorrow.
Echo is supposedly capped also; no first-person report from there either. I'd be surprised if Hyrum wasn't capped, but it's probably not safe yet. Newton should have safe ice and plenty of small fish. Bear Lake is open.
S.