Seeking your professional insights

My wife is currently on Tier 4 general student visa in UK, I'm considering an internal company transfer mission to UK, which I guess will be Tier 2 ICT visa.
1. Can my wife change to Tier 2 ICT dependent visa and not disrupt her study by needing to leave UK?
2. When I finish my transfer mission, but want to stay in UK maybe change to a new company, can she change back to Tier 4 student visa? And I apply for Tier 4 dependent visa and work for new company?
3. After 12 months cooling off, can I switch from Tier 4 dependent visa to Tier 2 General with the same new company?
4. Is there somewhere we need to apply from home country out of UK? we are now resident in Switzerland which might ends in the future and holds Chinese passport, so can we apply from Switzerland while resident still valid or we need to apply from China?
Thanks a lot!!