sometimes the safest way is to dash away immediately, since it's the only thing that's fast enough to avoid a down attack, even pressing A isnt fast enough to dodge it.
dainns normally just do A then dash, and since their wake-up A attack has a crazy range, generally they're safe.
Eirs: HS, SW, heal cancel, dodge, shout, tears cancel, etc...>_<
sieg: they can also use FDS(but not very reliable), blow, counter, etc
tia is in my opinion the worst at wake-ups. Her A attack is super slow, has a crappy range and a long delay after. Usually I use A SCA or A shuriken cancel