There may be others with more information, but i am pretty sure that although you can move from Tier 2 to Spousal/dependent visa, it isn't possible to switch from spouse visa to Tier 2.

This means that in order for you to sponsor them, they would have to return to their home country and apply for Tier 2 visa from there.

Lab Technicians don't appear on the shortage occupation list, so you would need to advertise the role under the resident labour market test and in the event that you were unable to find someone who already had the right to work in the UK able to carry out the role, ensure that the salary offered met the requirements to offer a Tier 2 visa (Minimum of £30,000 pa) in order to be able to sponsor them.

I hope this is useful

In reply to Teresa:

Hi,
Adding to Teresa's info, I've just looked at the list of positions that are not shortage occupations but that you can apply for a Tier 2 visa, and Lab Technician is not one of them, so it's unlikely that, even if you were a sponsor, you would be able to employ a Lab Technician on a Tier 2 visa. Which essentially means that going through the tortuous process of applying for a Tier 2 Licence will not help you be able to employ this person. Your Q2 and 3 are therefore a bit academic, but for info, you would have to apply for a sponsor licence before you can apply for a visa for your employee - but as Teresa states you can't "switch" someone from spouse visa to Tier 2 anyway. For Q3, IF you were able to sponsor your employee under Tier 2 then their spouse could apply to be a dependant of his/her visa - but it will still be time limited.

If there is no other visa option for your employee other than dependant (given Tier 2 is not looking like an option) then their continued employment will depend on their partner's right to work - but after 5 years of Tier 2 sponsorship, the visa holder can apply for Indefinite Leave to Remain and so then can the dependant.

Hope this helps.

In reply to Teresa:

Many thanks Teresa, that is very helpful.