> Also, I am not sure they will have enough power to provide in building service.

The issue for that is the wavelengths they are using. Their properties basically completely rule out any kind of in-building service, there needs to be a clear uninterrupted path between the receiver and the transmitter. (But they penetrate water well, so should not have a problem with clouds.)

FCC-18-38A1.pdf say 10.7Ghz - 12.7Ghz, that's a lot of spectrum. Depending on the SINR they get, which depends on the power, antenna sizes etc. you could get some pretty good speeds, probably above 100Mbps. But at those frequencies not likely to have any in car or in building. You can penetrate a building with higher frequencies if you have high enough power levels, but not from a satellite. So to use it you will have to install an antenna on the roof of your house.