LACP forwarding:
http://forum.mikrotik.com/t/forward-lacp-in-bridge/122451/1
For no lacp links workaround:
I use a tagged vlans on bridge and set dummy ip on ends, setup netwatch to shutdown the port if ping fails…
Workaround for only one crs305 regenerating signal :
On switch’s connected to the crs305 use lacp eaven if you have only one link..