SIN effectively is Ella and her kids. They're very much doing Ella's bidding and there's no sign anyone in that organization isn't on board with enslaving gullible people to fill their ranks with superhuman soldiers. Everything you attribute to Ella is also squarely on shoulders of SIN, and they bear the same responsibility.
While MUCH of SIN's superhuman backing came from Ella it's quite clear there are other forces among SIN and something we have yet to see is the other 'leaders' of SIN, we have seen Jared's father but from what I can remember there were other big bosses apart of that group no? Like Klaus's father. Although there is no telling the state of Klaus's dad's organization since well a major chunk got taken out of commission via MC and friends.
Most of that group were criminals and the like (I imagine some of them could of even been at that poker game from the Klaus arc or had affiliates there).
SIN while doing a bit of Ella's bidding
(as we've seen with Jared helping Charlie collect those what Ella wants while being a pedo) is most definitely doing their own stuff as well.
The recruiting of former soldiers while it could of been Ella who pitched that idea I doubt it since a lot of time has gone on between her being taken down and MC finding out info from Amber/Liz dad that it was recent, so Jared's pops has plans of his own (and probably the other big folks there too) while Charlie and friends continue doing what Ella wanted its clear someone like Jared's dad (who wants to remain in power) would do his own shit.
The interactions between Jared's pops and Ella (earlier on) also sets the tone that they are most definitely using each other although ol langy (that is his name now, accept it heheh) is most definitely the sub in this partnership.
On another note did we ever learn if Klaus's father had other superhumans under him? We know of the big 3 (Klaus, Dani, and Oscar) but was that all that group had or was there more? Also whats up with everyone having fucking cool power gauntlets (Dexter and Klaus's dad have one).