Everyone wants to work at the 'nice' bases which are less remote so it is first come first served in that respect - if you are not prepared for a couple of years of working away like that then probably not worth joining.
The remote bases have to be staffed (some people love it at them) so the contract requirements will inevitably come before family issues - I'm sure with certain exceptions. Sickness and injury inevitably mean some people will have to fill in on a temporary basis.
What Bristow have to provide is aircraft and crew to meet the contract - just like when it was mostly mil SAR - the only difference being that ordering someone has now mostly been replaced by offering suitable monetary reward for some of those hardships.
Good luck.
