[Q] Thinking of purchasing an M8.... topic

I am thinking of getting a Verizon M8, but I have a few questions. I am coming from a Galaxy S4. It's rooted, and I love the phone. When I got it, I did some research, but not enough to realize that only the phones with the MDK firmware could be truly rooted. I use Safestrap, and I am limited to a select few, but good, ROMs. Does the M8 have any of these issues. I noticed some of the threads mention "sunshine", and avoiding updates, but I haven't had time yet to dig my claws into it. What should I look for when I am looking?

[Q] looking to get an HTC one M8.. topic

Have decided to pick up an M8 and have been reviewing the process for unlocking the potential of the phone.. had a couple general questions about
If the phone comes with 4.4.4, is it still unlockable/rootable using the sunshine option? or am I out of luck?
Would there be a better chance to have an older version firmware if I pickup in store versus ordering it online from VZW?
I’ve been reading about how VZW likes to ‘lock down’ their devices using successive OTA updates.. If it comes with a newer stock firmware and I am unable to unlock/root, is it likely or possible in the future for it to become an option?

I appreciate your time and effort.
Cheers