Not everyone gets access to multi-attacks, and I apologize to everyone here for not making that more clear:
See, the reason why Rona can attack twice at such an early level and that's legal is because that is part of a
level 1 class feature is available to all monks. With the entire party now being at level 2, she has access to
Ki, which allows her to spend a point and throw out three consecutive attacks instead of two if she wanted.
Gnoll Witherlings and
Kavra can attack twice because monsters follow slightly different rules compared to PC's, and that's how their stat cards work. Not all monsters I throw at you are or will be able to attack twice, though. For example, the
gnoll warrior can't. Kavra's card is mechanically based off of the
Gnoll Flesh Gnawer from pg. 152 in Volo's Guide to Monsters, a supplementary book to 5E.
Unfortunately, Barbarians can't get a 2nd attack until level 5.
For Chaotic, while warlocks usually can't get an extra attack like barbarians or monks can, Gwen is a very special case since she's a hexblade. Warlocks get invocations as they level up, and at level 5, Chaotic can choose to go for
Thirsting Blade, allowing Gwen to make extra attacks with her pact weapon - same as you with your greataxe and Wan with her fists.