I am very wary of giving you a "definitive answer" to your query re. your wife. In the past, jobs in HR have been relatively easy to find, especially as the island tries to catch up with modern practice & legislation & to deal with the demands of the finance industry. Indeed, my daughter has found no problem in finding work (well paid - c£50-60,000) in this sector.
However, more recently the recession has bit hard on the finance sector, & there is record unemployment in the island at present (approx. 7%).
Hopefully, we are beginning to pick up now, but the "Golden Days" are unlikely to be seen again any time soon - if ever !
But, if your wife is well qualified, I would hope that she could find something relevant, or even in an unrelated sector. If that happens, she could expect a salary of £25,000 - 40,000. But, don't hold me to it !
A further word of warning; the finance industry has become pretty "cut throat" in the last few years. Continued employment within it cannot be taken for granted, as firms continually seek ways to cut their costs.
Generally, I would say that the job opportunities for well qualified & capable people are greater than in the UK, but maybe not by much !
As regards a "licence"; there is a "check" on incoming job seekers. Whether it takes such a form I do not know. You, as an ATCO, would be here as an essential employee , & unlikely to have any great level of restrictions placed upon you. That is unless things have changed in the last 5 years. As far as I know, the latest "outsiders" did not have a great level of restrictions placed on them (tends to be housing restrictions), & have had no problems purchasing housing. I would expect your wife to be treated much the same.
It would be worth 'phoning ATC & speaking to Lindsay (came here about 5 years ago. I'm sure he could "fill you in".
The fact that you will be a Civil Servant & essentially employed might well help your wife's prospects. The fact that this is a very "local" place with a residue of old fashioned priorities could give her an advantage with any jobs in the Civil Service; especially as they are trying to attract you !
That subject might well be worth mentioning in the interview when they ask you if you have any questions. But, be "diplomatic" if you raise the subject.
I used to be Deputy SATCO & a Watch Manager, & we would have regarded this as a relevant question from any applicants in the interview.
That's about it. Hope it all goes well for you.