For pair bonding you will need Home Hub 3000 most likely. When you switch back to 50Mbps you can use Home Hub 3000 as well.
Fibe Tv will definitely work with 100Mbps internet service. I used to have 25Mbps and Fibe Tv. I had no issues with TV service at all as it runs on different frequency than regular internet service. Later I switched to 100Mbps and Bell installed Home Hub 3000 with that service.
So I finally got some clarification and was able to talk to a rep on the phone the other day who was NOT a #2 or #3 (There for just the paycheck or commission), but was a #1 (who studies the industry in his spare time and is knowledgeable in the industry and can answer a more skilled question)
He took one look at my profile and told me even though my line can handle more than 100mbps over a single pair, bell does not have such profile active in their system, so they most likely bond 2 pairs of around 50mbps each and bond them at the modem level to make it 100mbps, and since i have an older modem that does not support bonding he said they have to give me the next modem up which is the hub 2000 which supports bonding. Also because my home was wired with 2 pair telephone wire (4 conductor) both pairs must be used and will run from the d-mark to the modem, whew, thank goodness i no longer have a wet loop (home phone line) cus if i did, they would have to run a new line from the dmarc to where my modem is located just for the pair bond. Unlike my parents house which has 3 pair wiring (6 conductor) 1 pair will be used for the first dsl line, another pair will be used for the second dsl line and the third pair will be used for the phone line. this is the ideal method, but bell does not wire up the houses the developers do so its beyond bells control.
anyways I thought about it and im quite happy with 50mbps. As for why we need that much, I have a family of 4 my wife is always streaming movies on her netflix, we have no cable tv so we use the internet to stream legal tv feeds to our living room TV, i have a small business and i need internet connection for doing off site backups and data transfers, and we have 2 small kids who like to watch tv episodes of peppa pig and other cartoons on the tablet, and we also have other devicesl ike a radio that streams internet music, an alexa which for voice commands, a chrome cast to cast videos to our tv, etc. all of these device use internet traffic,the bigger the pipe the better, less buffering, faster, etc.