I saw that no one has responded to you so I don't know if you have solved this or not. I wouldn't think that a wifi hot spot would work with Ooma. I had Ooma but dumped it because of poor call quality and dropped calls. Ooma's connection to the router / internet is so sensitive that it rarely works when connected following the instructions.
I you have gotten it to work please re post here and share it for other who may be interested.
I've tested my 4g at www.phonepower.com/speedtest and my test came back good for voip
For my 4g, I've got UML290 connected to a cradlepoint mbr-1000.
If anyone has a ooma with this type of setup I'm interested in your experience...