fish have no feet

[AirbusA321]

Are all these sentences correct and mean the same? If not, what are the differences?

1a Fish have no feet, hence they can't walk.
1b Hence fish have no feet, they can't walk.

2a As fish have no feet, they can't walk.
2b Fish can't walk as they have no feet.

3 Since fish have no feet, they can't walk.

4 Fish can't walk inasmuch as they don't have feet.

5a Fish can't walk for they have no feet.
5b Fish can't walk for not having feet.

 

[tzfujimino]

1b and 5b don't work for me.
(5b is grammatical, but 1b isn't.)
I'd put a comma before "for" in 5a.