When applying the kerdi membrane over the shower pan the hole was cut too small for the drain opening and there was some overhang on the small step in the drain where the drain cage assembly sits. We let the membrane sit overnight and then trimed the overhang to the proper size using the template (duh!) There seemed to be sufficient adhesion between the kerdi and the large part of the flange but we put a bead of kerdi fix around, where we cut. Should this be sufficient? Thanks

I'm sure you're fine. As long as the Kerdi is attached securely and not flapping in the wind, you're good. Use your own judgement knowing that what you are trying to achieve is a waterproof seal.

I usually Kerdi right over the drain and cut the centre out with a knife when I'm ready to put in the grate and lay the mosaics. That way I don't have to worry about dropping anything down the drain when I'm working on the walls and/or ceiling.