I'll give it shot
1. 5B: Arguably his best non-persona poke, great wide hitbox however can get low profiled by some moves (e.g. Chie 2A, Yukiko 2A and some sweeps) basically don't use it in their face that much outside of combos
2. 2B: Another great normal, pretty good anti air, can't be low profiled, cancels into most of Yu's moveset, first hit is also air unblockable, just try not to miss
3. j.B: If you going to air dash in this is probably what you want to use, it hits twice, can be converted quite easily into the sweep and has some use in combos
4. 2C: His best Persona poke, big range, can be converted into good damage in the corner, has a dash cancel however I'd only really use this in blockstrings where you think you might catch your opponent out, I wouldn't just throw this out
Side note: While it may be a hadoken style fireball, Zio isn't actually that good in most matchups, especially when Izanagi stays out for years, very easy to punished for just throwing it out