i think so. if you have a legit key, you should be able to do that. however it's still early to tell.

uh? if you're looking for confirmation on upgrade eligibility from current windows to w10, i guess it has been announced a few months ago. all w7 and 8.x users are eligible for the free w10 upgrade plan in its first year of release.

as for your question about preserving activations after upgrade, i believe it can be done. what we are still not sure is how it is done. also, answers to questions like how much do they charge? is there a discount for early adopters? still needs time to confirm. they might improve the current upgrade paths (which they kind of failed miserably at early stages) to make it easier.

so just wait and see

life-long? i don't think that's necessary haha you can always call ms when the activations failed.

alternatively, the way i preserve activations is to create system images. i do this whenever there are windows updates, so that when i do restore, the os will be activated, everything is in place, and i don't need to go through updates again and again. as long as i don't have much key hardware changes (especially mobo and cpu), this works well.