Apart from the WiFi requirement which is receiver specific, all the functions you mentioned are available on every Enigma2 receiver.
With regards to remote access, E2 was not designed with security in mind. Unless you setup up SSH keys/tokens, you are asking to be hacked. Setting a password is not sufficient. You would be better off remoting to pc/laptop and manipulating things on your mum's local network. So perhaps an old laptop she fires up when needed.
The other alternative is for you to manage and host the channel list elsewhere and get receiver to fetch them. There were plugins to do this a few years back but you can use a script.