You've got some nice abilities on these cards. With a little editing to wording to make them more "official" and some tweaks to their stats, you've got a great start to some cool customs.
Bazooka Unit
For simplicity's sake, you might drop the separate rolls for the attack. Maybe lower it to 3 attack against the target and all adjacent figures. I see where you are going with it, extreme damage to the target and splash damage to those around it. Bazookas are pinpoint weapons designed to penetrate armor and destroy a single vehicle. What about keeping the attack at 5 and add "if the chosen figure is destroyed by Rocket Launcher Special Attack, roll 2 attack dice once for all adjacent figures. Each figure rolls defense dice separately.
Apache Archers
Wind Walk is a cool ability, but with a base move of 7, it may be a bit broken. They are moving on foot, so a base move of 5 might be more appropriate. The other option would be to reduce the amount of the bonus movment.
Wind Walk
If Apache Archers do not attack this turn they may move an additional 4 spaces.
Aramist has some neat abilities. I've seen attacks like Enchanted Arrows that had cleaner wording, but I can't remember what figure had them. Let me give it a shot
Enchanted Arrows Special Attack
Aramist begins each turn with 5 attack dice. When using Enchanted Arrows Special Attack, Aramist may attack with 1, 2, 3, 4, or 5 dice. Aramist may continue attacking until all attack dice are rolled. Aramist may attack the same or different figure with each attack.
I think it reads something like that.
Missile Shield
Aramist and all friendly, adjacent figures may not be targeted by normal, non-adjacent attacks.
Hope this helps.
Also, if you are interested in making your cards look more "official" I would recommend visiting GreyOwl's Customizing Tools page
here. He has templates for official Heroscape cards, dozens of his own creations, panels, fog, class/personality listings. These are usable with Photoshop and GIMP (GIMP is what I use).
Keep up the good work! And by that I mean playing games with your kids!
(Proud father of a 6-year old Scaper)