Yes, basically any /A is viable.
I do agree with you, the Assassin profession is definitely based off of the Ninja, since we are in Cantha, which is based off of old Oriental ways. No assassin would really be using smoke screens, that's the sign of a Ninja.
Anyway, as Jetdoc already stated, Me/A is viable, but so is N/A (not the accronum for Not Available

). Teleport to, do your touch skills/spells, teleport away. Basically, teleport to foe for healing. Bite for more healing, give them a non-vinerial disease, and teleport away.
Mo/A, healing is good. Uh, oh, monsters coming to attack the poor monk, RUN!!!!, or teleport to other people using an assassin teleport skill (enchantment).
Rit/A, weapon spells; hard rez; communion spells
There are many ways that the assassin can help or be helped by the primary or secondary profession. Look around for build and see what can work, what might work, and what does work.
Have fun.