Your concept seems to add up nicely. When doing micro management in small steps, you need to remember that this way you cannot let a player control many units at the same time.
What sunandshadow suggested was a 1:1 relation of movement squares and action points. Units have each a different amount of action points, which represents their agility. Attacks all differ in cost. (PoxNora)
You dont need to have multiple actions for multiple attacks, btw. In Battle for Wesnoth a unit hits several times in one attack, (rolling for each attack separately).
Also, i want to point out that combat roles imho are.. a lot of fun. It is important that you have unit types specialized for certain tasks (classes), which the players can easily identify from the visuals. It adds flavor and tactical depth. Id research a little in that area.
PS: i hope i do not appear to be mansplaining, im actually an amateur, too
Rolling all the attacks up into one click event for the user might not be possible for my game. I've been experimenting with different designs and I'm starting to realize that forcing the user to attack once won't allow the user to attack move and then attack again in one round. In addition,each unit in my game has the ability to attack with each weapon they are carrying This is important for my game because of the weapon type vs armor type rules I've created. A bashing weapon vs chain mail will do more damage than a slashing weapon vs chainmail. There might be a way of automating these tasks for the user, but I'll have to give that some more thought.
What I've done at this point is assign a MaxUseCount per action per unit turn. What this means is that some actions can be perform once per turn and others are only limited by the action point count.
One thing I'm debating right now is how to implement actions like parry and disarm. I started out by placing each of these actions under each weapon attack. That way if you had a dagger in one hand and a sword in the other, you could parry with one weapon and disarm with the other. I think that's a real choice in combat that I can give the player, but building it into the action system is a bit confusing.
For my game I really don't want combat roles that are linked / hard coded to each classes. I don't want a fighter to always be a tank. I want the concept of combat roles to be something the player does during his build / level up process. I mean what is wrong with a wizard who is a tank? If I do have classes, then each class will be able to support any role. I also want mixed role concepts to be just as viable as single role builds. I may even want to support multi-classing.