It's hard to forget things that are related to Tekken. Maybe you get rusty with your main, but there's only a couple of things to focus on during your fights compared to DOA anyhow, the most you'll miss is all that damage that you might leave on the table.
It was mainly stuff with anna I forgot, like I forgot which moves transition into Chaos judgement at first and I completely forgot she had a wavedash XD
I like Anna because she's a good whiff punisher and very versatile, she also has great lows that I like to abuse to get also use reaction and open my opponent up. Hwoarang I can't say since I don't use him, but for Anna you kinda have to think while using her since she has so many highs, slow mids and lows that become useless if you condition the opponent too soon.
Yeah, it's not that hard though, her lows are very good, and as you said yourself, she whiff punishes people very well. The thing with Hwoarang is:You HAVE to know a lot of things as a Hwoarang player to outsmart your opponent, because those Flamingo "loops" at higher ranks won't work, that, and he's not the greatest whiff punisher. or punisher in gereral.
Sometimes I find it easier to play with my secondary team cause of their punishing and whiff punishing abilities, and that they are not too complicated to use compared to my main team.