You might have to click on "bypass passcode" for that. Not 100% sure, but that would make sense.
No passcode on my phone and I tried it with that option turned on and it still doesn't work.
Yes both ways work for me.
Hitting the quick reply button (next to trash can) opens the mail app for a second and then brings up the message itself which I can reply to.
Or swiping from left to right opens the message and I have the option to reply or delete.
What version are you on?
Doesn't work for me. I'm on the most recent beta - 5.0.0.14-45.