Which brings me to the death of non aligned squadrons. I think that's a real possibility. You can't have everyone pulling every which way, or can you?
It really depends what the squadron is up to.
There's no mechanical penalty for having players pledged to different Powers (or none at all), and if the Squadron is aligned to one Power the players in it don't have to be. If the players are in different Powers then they're probably not going to be organising many Powerplay-focused events as a Squadron (though they
could all team up to undermine a Power that none of them belonged to) but it mostly won't affect other sorts of events.
Not sure if it was considered? My opinion is that in many cases it will not help squadrons who own their own faction.
I think the reasonable choices for a squadron built around BGS play are:
1) Ignore Powerplay as a group entirely. If you're not pledged, it makes little to no difference which Power is dominant in your systems - the days where Powers had preferred government types are over, it makes basically no difference which minor faction is in charge of a system. Individual members can pledge if they want, of course, and can probably find a way to get some merits without interfering with (and in some case for the same action as) their BGS work.
2) Because of the moderately-strong overlap between Powerplay reinforcement activities and things which increase the influence of the system/station owner, if your faction's territory largely falls within one Power, then if you all pledge to that Power you can get merits as a side benefit while doing faction work. Some of the Power bonuses (increased bounty or exploration payouts, faster reputation gain) can be useful for enhancing BGS work too - but only generally apply in your own Power's space. Promote a local system to Stronghold for a chance at a Stronghold Carrier and your own personal Shinrarta-class outfitter in your chosen system.
(If your territory falls between multiple Powers, pick one and gradually flip the rest)
3) Because
most Powerplay undermining activities either don't directly
harm the controlling faction, or can be directed against secondary factions instead, you can take a "kick them out" approach and try to make your space fully independent. You'll need to temporarily pledge to a Power as a flag of convenience while you do this (but you don't all need to pick the same one) and as you don't care about rank, you can just unpledge when you're not working the Powerplay side of it, or even switch pledges whenever convenient [1] to maximise your ethos bonuses. Mainly target Fortified and Stronghold systems for this because the Exploited ones can't survive without them.
All of those should be viable options.
[1] e.g pledge to Delaine just before you go on a murder spree of Power enemies, then switch to Kaine before handing in the escape pods you picked up along the way, then over to Torval for a bit of Odyssey settlement work. Though ... be very aware of the
location requirements for each activity if you're going to do this, as the travel requirements you give yourself might make the 50% ethos bonus you get for it not worth the hassle.