Sorry if these questions have already been answered--I didn't see them on a quick skim through the thread...
1. When you place Genestealers after revealing a blip, can they be placed on diagonally adjacent squares? (I'm pretty sure the answer is yes, as the movement diagram earlier in the rulebook shows 'adjacent squares' as including diagonals, but my opponent was a bit grouchy about it as he found himself one square closer to my 'stealers than he'd expected and ended up losing a Marine...)
2. If a blip is near a Marine but out of his LOS (e.g. to his left), and he makes a turn action to bring it into his LOS, thus causing the 'stealers to be involuntarily revealed, can he combine that turn action with the free shoot action and blast one of the newly revealed 'stealers? In other words, can he declare 'I'm turning and shooting at that blip' even though he doesn't know what he's shooting at til after he's turned?
3. We currently play that CPs used in the 'stealer turn can be played on any Marine, not necessarily the one who saw the 'stealer do something (since he's communicating with his team). But if a 'stealer makes an action within LOS of a Marine on overwatch, does that mean that he shoots AND that the Marine player can use a CP to respond to the 'stealer? If so, is this considered simultaneous, or could he perform the overwatch shoot action first, then use the CP to unjam if necessary, before the 'stealer does another action?