Sadie and
Eliza - yes. The other girls name's, I think should be used as short versions of their 'proper' names.
Liam is a name in its own right anyway - it's the Irish version of
William.
For the rest, I guess
Sam,
Cliff &
Gene seem ok as names (I don't know what
Gene is short for). Though I would use none of them...
http://www.behindthename.com/pnl/167578