Re: windows 10 on HTC?
Probably.
The questions are:
Will HTC make it available to its phones? (The 8S? Nope. 8X? The odds are slim. One M8 for Windows? I'd like to think it'll happen. 8XT? ehhh.)
And if HTC makes it available to a given phone, will the carriers wave it through, delay it, or reject it altogether?
If no for either of those, how well will MS's Preview for Developers/Windows Insider program work? We don't know yet.
CONCLUSION: Unsure.