Any other characters that might help me get hold timing and defense down a bit better maybe?
Bayman, Leon, Leifang, Bass, Tina - since they are perceived to favor holding often! If you're trying to get hold timing down, practice against any ninja! Oh, look - my avatar! The spazzing against her is ridiculous! (I'm serious - "She's too fast!") Christie ... no one is worthy of being her toy! Helena - she is no slouch either!
If you wanna get fancy and do advanced holds: Bayman, Leifang, Ryu, Kasumi, Hitomi, Mila (she fits the above, too), Ayane ...
Piece of adivice (and people shun this), but even when you get to where you can hold very effectively, it is not a bad option to
block because you can get punished. This is unwise against Bayman, Bass, Tina and don't ever do this against Alpha! There is no reason to take more damage than necessary! 100 > 150!
Also, if you wanna get good at holding, slow down! Defense is meant to be played slowly! I'll use Alpha as an example! There is nothing wrong with beating her defensively (except it being "too hard"). I've played many who more often than not take the easy route usually ending in no-contests. However, games are much better when they don't! I've seen improvement from players whom I've given this advice to whether I've won or lost these fights - I enjoy them much better.
Defense and defending oneself requires lots of time and patience! You won't win all the time, but that isn't the goal here! Likewise, being flashy shouldn't be the goal on offense all the time either. Pace yourself! Your offensive and defensive growth will come naturally!