You were warned, and I will say it again, spoilers are in my post....

I am about to free every synth in the Institute for the Railroad. I have decided to side with the BOS and Minutement. I still haven't done the Battle at Bunker Hill either.

1. I am wondering if I can get through the Battle at Bunker Hill without making enemies with anyone.

2. How do I proceed in a way that lets me stay friends with BOS without pissing off the Minutemen.

3. Can I free all the Synths and still be friends with BOS?

I ask these questions because I have read that the message I am suppose to get about how my choice effects my relaitons with other factions doesn't always show up. So I am trying to figure out how to proceed here.

And holly cow, is this games story line have too many factions interwoven with each other?

Pretty sure you can't piss off the Minutemen by doing ANYTHING. They are pretty laid-back folk and seem pretty detached from the Institute-BoS-Railroad factions.

At Bunker Hill, I sided with the Railroad and killed both Institute ~and~ Brotherhood attackers... later on, I "confessed" to Father that "Hey, we got our asses kicked"... I don't recall the Brotherhood mentioning the fact I'd shot down several of their Vertibirds, either.

In the course of freeing all the synths, you'll be going against the Institute (in a big way) so I imagine the Brotherhood will be quite happy with that. There are a lot of interactions between factions and the ORDER in which you do things can change how things play out, I suspect. Before you reach a point of no return, you'll get a pop up warning that, if you do this or that, then you will alienate a given faction.

Well, except if you, for example, are told by the Institute to kill all the Railroad folk.... the Railroad folk will not aggro on you ~until~ you start shooting (since you could always choose NOT to shoot them). So in that case you don't get a pop up warning, but it should be obvious that if you are told to kill all the Railroad, and you ~do~ then the Railroad will not like you.

1. Yes, it's possible to got through the Bunker Hill battle without attacking anyone. You just need to be a member of that faction to not get hostility

2. Nothing you do for the BOS angers the MM. In fact, the MM are the backup option if you angered all 3 main factions so you can't really anger them

3. No. Doing the RR and Institute questlines require you to automatically make the BOS hostile. Meanwhile, the BOS quests ask you to kill the RR and Institute. You can't free synths and keep the BOS alive. You'll have to give one up.