I apologise for the lengthy topic in advance

My questions are following:
1- Can I apply for a new tier2 visa from outside the UK regardless of having leave to remain as tier4 since I maintained my residence outside the UK? would that result in my current tier4 automatically cancelled?
2- If I apply for interruption of study for 4 months, will that result in my current tier 4 visa be cancelled? if yes, how soon after applying will the visa be cancelled? will I be subjected to any restriction on how fast I can apply for a tier 2 visa?
3- Since I have finished all taught material and all assessments, if I arrange with my department to submit my final dissertation (the final requirement to get the MSc) by July, and get an official letter stating that my course is expected to end in July, would I be able to switch my visa in April? would this be accepted by UKVI?
Thank you in advance