With that in mind, I say we play to our strengths and seduce Heston with wild debauchery, but then worm our way into the remaining family's good graces. Talk with Chase about business opportunities, and Brock Sr and Nora about flight and the possibility of developing our own hellpowered aircraft.
We have our own helpowered aircraft. We can pretty easily give them a piggyback ride on a Stone Shell.
Probably not very fast, high, long, or comfortably, though. In all likelihood they appreciate the art of controlling an aircraft themselves more than yelling at a minion. Or at least the two flying now probably do. Maybe the others would like a gargoyle chariot or something.
Why befriend these people? It would be simpler, and satisfying to at least one of our henchmen, to just hold one or two family members hostage until we're done.
We don't know how long that'll be. Keeping a high profile hostage for six months is no small feat.
It introduces complications to everything we do. Remember that Phase 2 is getting Cajun Jack on board, and if his rich friends are looking stressed and nervous while introducing us that might not be great. This also scales with the above time issue; the longer a precarious situation holds, the bigger the odds of something about it going sideways.
Finally, playing nice gives us more side opportunities. Maybe we really can start developing zero emission flight craft for the rich and evil. Maybe there are business opportunities waiting for a demonic investor. Maybe Brock Jr would make a great torturer and prison guard. Schmoozing gives us all kinds of options that threats probably don't.