1) When a unit attacks another unit, that units gets to retaliate (if it can) against the unit that attacked it.
2) Action Points = 1 + Your Combat Speed.
3) Moving a tile uses 2 action points.
4) Attacking and casting a spell uses 1 action point.
5) The placement of units on a map will be based on the the composition on the units going into the battle.
6) Units will have various special abilities (that's why the action tab looks so blank right now).
I definitely like the Action Points (AP's) idea. It lends to that "X-Com" tactical battle feeling. AP's have been used in a Lot of turned based games. Everything from X-Com to Fallout 1&2 to RPG's like Baldur's Gate in which the AP's were in the back end and the player didn't see the actual AP's but rather saw them as a turn counter based on a invisible timer.
Elemental I believe, because of it's rich variety and the fact that it is a Fantasy game, has the chance to be truly Unique in the way AP's are handled. As the game evolves down the line we'll be seeing more and more uses for AP's and every use will have different effects and implementations. By tweaking the costs of AP's for various actions Elemental will have it's chance to stand out from the crowd, let me give some examples.
Most games handle this by having a pool of AP's and only having the costs change based on what types of actions are used. For example in X-Com, even though one soldier may have more AP's then another, kneeling or standing will use the same amount of AP's for those actions for both of those soldiers. This is how most games of this type handle this. AP's change based on a units experience level and how attributes are spent on these characters. This is the same old, same old, that fits the mold for everything because this type of system is easy to do and seen as intrinsically "Fair". I think this can be changed to add better variety and to also tweak balance when needed. If it costs a Man 2 AP's to kneel, why should it cost a Dragon 2 AP's to kneel? Especially when that Dragon is so much bigger than a Man. Maybe a Dragon should use up more AP's to kneel but also have a larger AP pool to draw from. Deciding to tweak variables by unit type will give you the ability to balance different unit types against each other and allow for a greater variety for their uses as different unit types have different abilities.
Here are 6 quick ideas based on the early 6 things you'd like to do. Feel free to draw on these and extrapolate or add ideas where needed, or to ignore them entirely and do you own thing. Which ever you prefer 
Note: ALL Values below are "Hypothetical" values. For the examples given you can insert whatever values you want based on what they actually are in game.
1) I would say to have the AP's used by the unit that is retaliating come from only one turn. Either the turn in which it was attacked, or the turn after. This would add strategic depth to battles by causing the smart player to "Save AP's" for defensive actions. If I move a unit and attack or do another action that uses All that unit's APs then maybe it shouldn't be allowed to retaliate. Or if it has No AP's and it is allowed to retaliate, have that retaliation not be very successful. Why? Because if a unit is completely out of AP's that simulates the unit being "Exhausted". If a man runs for 1/4 of a mile and then suddenly has to react quickly to something he'll have a much slower (and hence less effective) reaction than if he had just been standing there doing nothing until he needed to react. If the player knows a unit will be attacked then a smart player wouldn't use up all the AP's on a offensive move unless he knew that offensive move would wipe out his enemy. If the unit is going to be attacked at the end of the turn the smart player would save AP's to bolster the units defense. Perhaps add in a modifier that converts left over AP's to a slightly higher defense rating. Example:
Unit A has 30 AP's. During the turn unit A uses 25 points in moving and attacking and when done has 5 AP's left. If the player chooses not to move unit A those remaining 5 AP could add 5 points to the basic defense of unit A against attacks during that turn. (the values are completely made up here as I have no idea how many AP's are used for what)
2) That seems like a good way to handle it. You might want to also consider tying Dex to AP's as well. Dexterity, to me at least, leads me to think that something with a higher dexterity could move a little more, and faster, than a unit with low dexterity.
3) I'd like to see the costs of moving in AP's be based on the Type of Ground being moved over. Flat grassy plains would take less AP's to move through then a dense forrest. A dense forrest would cost a different amount of AP's to move through then loosely packed snow. Etc Etc. This also lends to different types of units being able to move over things at different costs. I.E. a Swamp Dragon may only use 1 AP to move through a swamp, while it costs a Man 2 AP's to move through that same swamp tile. This way you can tie certain unit types to their favorite terrain types. Like having a Ice Golem move quickly through Ice and Snow, but move slowly if forced to travel through a desert. Varying costs per terrain type has a much better feeling to it I think.
4) How about having this be variable on how powerful the spell or attack is? The stronger the spell or the stronger the attack it will use more AP's. If a man can swing a sword and do 5 damage at a cost of 1 AP, why should a Wizard be able to cast a spell that levels a small army for 1 AP? If a Man can shoot a bow at a Dragon for 1 AP, why should it cost the Dragon only 1 AP to breath fire on the entire army? I understand the need to keep costs simple so you can balance things easily in the beginning, but, I think you could add a Lot of depth to this if you tweaked the AP costs of actions based on how strong those actions are. This also allows more variation in actions, like Mêlée attacks and "Special Moves". A Man can swing a sword normally for 1 AP, OR, that same Man can do a whirlwind attack with his sword and it might cost 3 AP's.
5) I'd like to see the player given the chance before battle to place their units where they want before the battle begins (within a certain range of course). This way I can put my casters behind my mêlée units or put my archers up front and then move them to the rear during the battle if my enemy advances. Tactical battles would need to have another "Phase" added to them called the "Deployment Phase". You arrange your units how you want them to start the battle, then you hit "Begin Battle". To give an example, the Total War games do this as do many others. It honestly doesn't matter if it's for a turn based battle system or a real time battle system. This works good for both.
6) Very cool
. To give more variety to these special abilities I would suggest having the AP cost for using these abilities vary based on the ability its-self and the stats of the unit using the ability.
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Those are just some general ideas to expand upon your 6 points. I think the battle system is shaping up nicely so far. Also, the animations in 3C are much improved compared to 3B. I noticed you tweaked the animations for attacks so that both the attacking And defending unit step up to each other. This looks much more natural then having the defending unit step up to get hit. Well done indeed 
You guys are doing One Hell Of A Great Job!!!!! Keep it up!!!! See you on the battlefield. 