Will Android 4.0 (ice cream sandwich) be released on the HTC Sensation and Samsung Galaxy S2?

Answer 1

there are no official statements by most companies what phones are getting the updates and which aren't.

if your phone doesn't qualify for the upgrade, you can still get it by rooting the phone if you choose.

Answer 2

May be Yes,
Recently
Rumors : Samsung to unveil Android Ice Cream Sandwich phone on 19th October

May be Possible that version on the Sii

Answer 3

Unlikely, there will be new phones out by then.