That does remind me that I forgot to say anything about equipment and Spacesuit upgrades themselves.
Your spacesuit has a certain amount of "Slots" that upgrades can be applied to. (The amount of slots is increased by skills.) And most upgrades come in tiers. The second tier of a fireproof suit upgrade, for instance, takes two slots, but is more effective.
Your Spacesuit also has some similar slots for other, non defensive types of upgrades. Items like the Rush Boots from Pikmin 2, that increase movement speed, or the effectiveness of certain skills/rolls.
Some equipment also effects Pikmin directly. There are items that increase the abilities of Pikmin passively. (Right now I just explain them as radios that play tunes that, like the 'marching' tune, effect the way Pikmin act, increasing their abilities. They will probably require batteries, or energy cells of some sort to operate.)
How do you plan on handling movement? How close do players have to be to exchange Pikmin, and how will you communicate the location of unattended Pikmin to the players?
Haven't gone too far into that. As far as players exchanging Pikmin goes, within Whistling range would probably be sufficient. And, as for the locations of unattended Pikmin, probably by using the description of the area to point out where Pikmin are left, but I won't be reminding everyone that they're leaving Pikmin lying around.
Player abilities and skills should produce different results when used with different Pikmin types.
I haven't gotten too far into abilities themselves yet either.
I know this isn't what you mean but; The different types of Pikmin (And the Leaf > Bud > Flower varieties) all have their own stats, so abilities would naturally produce different results with different types of Pikmin. Using that "Power Throw" or whatever it'll be called would be a lot more effective with Purple Pikmin, but be a lot less effective with White Pikmin.
The Abilities and Stat Finalization are all that really needs to be done before the game is in a ready enough state to be started. I've done quite a bit of mapping already.
Fake Edit:
Oh, and I just remembered the Sprays from the Second Game. Can't believe I forgot about them, and I
was missing a fourth Other/Utility Skill. Chemistry?