Small ship miners are always fringe. If you are running for yourself and your small crew, you aren't running with a big MegaCorp (Bureaux). So the corps are legit and conformist but they mostly inhabit high-value locations that have been scouted by corp scout teams or more likely, freelancers. The other guys that do the speculative stuff and that mine the marginal areas or the areas just being opened are going to be the small ship belter/miners and those guys are like any small crew - every one will be a bit different. They may sell their stuff to the same megacorps, but their day to do is likely fairly unique to each ship. Sort of the mining version of Firefly.
Note though that in any stratified culture where 'the betters' (be they legally more elevated - e.g. titles - or just financially elevated - e.g. the 1%ers), anyone that works for a living with their hands (tilers, carpenters, ditch diggers, garbage men, belt miners, etc) will all be scene as the underclass, the working class... and will be a necessary thing but never to mix with 'their betters'. This means freelance belt explorers or miners are always going to be looked down on by: Megacorp middle management, Navy functionaries, local system authorities esp tax/customs patrols, local revenue collection agencies (tax folks), and so on and so on.
I think that also goes to the belters looking at those sorts of folk as pompous, arrogant, incompetent, lazy, evil, parasites, etc. They might respect a Star Force Marine, but they'll probably share a mutual dislike with the Destroyer CO or the local Navy's Custom's Enforcement Corvette.
I think they fit in more with Scouts, Bounty Hunters, most Law-Enforcers, most enlisted military, and others who 'work for a living', except they are less stuffy and proper than some of the servicemen and women.
I think the Ziru Sirka, just like anyplace else, would have major mining Megacorps running stuff and those would all be licensed to the nines. But there would be smaller licenses and they might not be too hard to get in fringe areas for any ship that wanted to do belt exploring. They'd want that done and its risk the MCs don't have to take (someone else's dime). And as you say, if you get all of your trouble makers to ship out to the belts... well, that's one social problem solved! ;)