Has anyone given their player's hirelings?

A few times. They've had a few droids and some goons on loan from the organization they're working for. I try to run them as lowkey minions and not steal any of the PC's thunder. It definitely helps with larger ships to have the random turrets and/or fighter compliment crewed by the basic hirelings.

I think the trick is to just keep them very generic and in the background, like extras in a Star Wars show.

It also depends on how much detail your group likes to keep track of. I tend to ignore things like fuel costs, payroll, etc. But some groups have that one spreadsheet person who loves that kind of thing. If yours does, don't be afraid to offload some of it on that player.

I've done two different things in these scenarios. When my players got a larger ship I had a trusted NPC who could captain it and manage the minutia of crew while the players did their own thing. They then could discuss with the NPC missions they wanted their crew to undertake that had the chance to bring in income or make progress towards upgrades. Or they could use the ship as support in whatever they were actively doing instead (though a big ship was often balanced out by big problems).

After they joined the rebellion, they had alliance crew, though they also ran missions near the end of the campaign to recruit crew members from allies they had encountered during the campaign by providing further assistance or favors.

Essentially I just tried to keep managing the crew narrative and didn't try to get too gritty with costs or numbers.