Yikes!!!!! Scary for sure!!! I've heard of ball lightning before. What a phenomena. Glad you mom was okay, as well as your house for the most part.
The fact they are all cordless was probably the reason they went out. Cordless phones are always plugged into electric power. We have a cordless in every room in the house (lots of phones here) but we still keep two phones that are not cordless (so 2 phones in 2 of our rooms, kitchen and family room), still plugged into the old phone outlets, no electricity needed. Our cordless do not work either when power is out, but those 2 non-cordless still work with no electric.
But I do believe you, and your hubby.