Ok, so I was about to complete "The Molecular Level." I had abstained from all spoilers involving the fate of Shaun, so I didn't know what was coming next. I was expecting it to be something like the Terminator shooting up the police station. I get in full battle rattle, with power armor, minigun, missile launcher, fat man, all that good stuff. I honestly expected all Hell to break loose. You see how wrong I was. Anyway, the logical choice, going off that presumption, would be to enlist the Brotherhood's help with this, considering they have an army of knights in power armor, vertibirds, and a giant freaking zeppelin. So, I go into the Institute, give the datatape to Proctor Ingraham, do a couple missions. Then it dawns on me that at this point the game is no longer on a specific track. I go on the wiki, and find out that eventually you have to pick a faction. I'll get to that eventually but right now I'm milking the side quests for maximum XP and rewards.
For anyone who is going to say tl;dr, here's my question:
Can I still get the Minutemen ending? I tried talking to Preston and Sturges, and they don't tell me anything aside from the normal settler/companion dialogue. I saw something about getting the datatape back from Proctor Ingraham, but no dice. But, that may be because I am currently on the mission "Liberty Reprimed."
Second question: Is it possible to have several separate, parallel, save files? Once I run out of the side missions I would like to play as each faction, but I'm too cowardly to fool around with my current save file and would rather ask a Hard Knocks Alumnus than enroll myself.
Edit: I neglected to mention this is on the XBox One.