Oh boi, here it goes:
Abilities:
-People like Jeff or Duster should add the habilities that their items gave them, like for example, Jeff should have
Life Stealing with the Hungry HP-sucker, and Duster
Statistics amplification/Reduction with his Items.
-Ness could have
Astral Projection (I think this is the corresponding abilitie) since after he ate the cake in Summers, he was capable of seeing exactly everything that was happening with Poo, even when he was at the other side of the planet.
-The creation of Magicant could also grant Ness some powers, like
Spatial Manipulation,
Reality Warping, or even
Matter Manipulation if we consider the fact that even after absorbing it, he still had the Magicant Bat in the real world, wich was created in Magicant. (While Magicant is the representation of One's mind, and that it is found in One's consciousness, that doesn't take the fact that Ness still
created it, not imagine it, just becuse is found in his mind, that doesn't mean is not real)
-Giygas should have
Spatial Manipulation and
Attack Reflection(probably for his base form, since in this form all the attacks trown by the kids at him get reflected back at them), since is specifically stated that the battle against his Low-2C form was taking place in another dimension. He should also have OHKO since he can use a stronger variation of PK Flash.
-Ness should have
Attack Reflection aswell, since PK Shield
ß reflects back 50% of the damage taken back at the enemy
-Giygas could potentially have
Existence Erasure, since it stated by Porky that he would eventually "eat the kids" and destroy everything in that dimension and the Regular Universe. Considering that the only thing that permited the Kids to come back to their Regular Time was their spirits, and the fact that if it wasn't for the players help, the kids would have eventually lose, is not very crazy to state that if the battle would have prolonged, the kids would have been completely destroyed by Giygas, both in the Physical and Spiritual way.
Resistances:
-I think that most profiles should add some resistances for the items that the Kids can equip, like for example, the Frankling Badge should grand resistance to Lighting manipulation, since all lighting attacks get redirected to the caster of the attack. Also, there are the Bands and the Bracelets, that grant resistance to Lighting, Fire, Ice, Mind manipulation and even to OHKO attacks. Since altmost anyone of the games can equipp this items, this should apply to everybody.
-The kids from EarthBound / MOTHER 2 should have resistance to
Spatial Manipulation, since even with Giygas twists and turns of the dimension they we're battleing, and even in the moment where he created it, they we're just fine (Still getting destroyed tho)
-I don't know if they should have
Time resistance, since even after fighting a reality warping monster in the past and surviving his changes trough time, they apparently come back to the future with no apparent change in the universe. (That, and surviving in his dimension)
-Both versions of Giygas should have Resistance to
Mind Manipulation, since neither of them gets affected by Ninten's or Ness's Mind Attacks. (This would include being unnafected by Statistic Amplification or Decrease, and even Power Nullification)
Equipment:
-As stated above, the items like The pendants, Band and Bracelets should be included in everyones profiles.
-The important items for the user, like Jeff's inventions and Duster's tools should be specified alongside their Power and Abilities (Ej:
Statistics Amplification (Defense spray) for Jeff, or
Sound Manipulation (Siren Beetle) for Duster.
-Altmost anyone from Mother 3 should have OHKO, Explosion Manipulation, statistic amplification or Shield killing via items, since anyone can use them. (I'll explain the items later)
-Lucas should have
Self-Resurrection with Magypsis Memento. (Up to 7 times)
-The "instant pills" should also be added, since they are kinda like temportal drugs that boost the users stats during the fight.
-Many items that can affect enemies completly, like the Viper or A Super Plush Bear could be added to the main party eqquipment, and even in their Power and Abilities.
Oh boi, there goes at least the one's that I think have enough fundaments to be added to the profiles, but now I want to discuss some stuff that could potentially be game changing for the series/verse.