I doubt if anything has changed much since the other posts were written. The recession is still biting both the public and the private sectors in Finland. Government money is being channelled into teaching Finnish to foreigners.
CELTA/DELTA are unknown in the public education sector. Weird yes, but true. The basic requirement for teaching in the state school system is a Masters degree in the subject you teach.
The private language schools hire freelancers on an ad hoc/casual basis; there are very few full-time (salaried) contracts on offer. That said, it is not difficult to set yourself up as a sole trader or work with what the tax authorities call a freelance tax card.
So, given that you have experience and good qualifications you should be able to get some hours and gradually work up to a decent workload. Try Tekmil (one of the biggest), EF, AAC Global (or whatever they are called nowadays). Jobs are also offered on the Ministry of Labour website
http://www.mol.fi
If you have other skills (translating, editing, copywriting etc), you might stand a better chance of finding salaried work. Try following NeAT (Nordic Editors and Translators) on Facebook as they share job openings in those fields.
Sometimes Finnbrit hires new IELTS examiners but I don't think there are any vacancies at the moment.
The job prospects here are not great compared to eg Spain, simply because every kid leaves school with roughly B2 English (or better) and there is a large army of Finnish native speakers who are highly proficient, qualified and experienced English teachers and they generally secure most of the public sector jobs. Teacher training (equiv. PG dip) is provided by the UAS (Universities of Applied Sciences) and/or by the Universities. There is no CELTA/DELTA teacher training anywhere in Finland. So, after your wife graduates, it might make sense to move on. Everyone who graduates with her will be chasing the same jobs...
In a nutshell, I think you will find work, but maybe not enough to support a family living in the capital, and pay the tuition fees. Is it Helsinki you are moving to?