About the hitting positionals while executing mudras thing, let me tell you why its not an issue. You may not realise it but dragoon is in a similar position when it comes to that issue, executing a jump roots you in place, so it means you literally cannot execute a positional and a jump at the same time. So what do drg's do? They go for the positional at a point in their rotation where they dont have to jump in preparation.

It goes for every job that has infrequent positonals, say every 5th attack you do has a positional, that means you have a window of 5 GCDs to move to the opponents flank or rear, so you can just choose one where you dont have to do a jump or in NINs case a ninjutsu and prep for the positional.