Current State of Memorable, Sincere, Kindness Ambassador etc.

kusurusu I use the cheat Traits.equip_trait KindnessAmbassador in my game. I haven't see the others in lists of trait cheats though.

I sell the growfruit challenge planters in retail lots or add them to a house before it's occupied so that they're unlocked in the build catalogue. I also keep spotting items in debug from challenges that we don't have anymore. I recently found the Positivity Challenge posters there, I'd never seen those before and they're really cool.

it would be so nice to have those added, even without the challenge they happened with being in the game... i mean, they're already coded and there, what's the deal...?

cheat codes for Memorable and Sincere are pretty straightforward: traits.equip_trait trait_Memorable and traits.equip_trait trait_Sincere respectively

as for objects I'm not sure if there's any cheat but here are the planter pot object IDs: 127451 (normal) and 128781 (perfect)

oh and btw, in OP I meant unlocking them without any cheats

For the planters you can use the bb. ignoregameplayunlocksentitlement cheat. I use mccc to have it always turned on because I want to use all assets in the game. I agree with you that there should be a way to achieve these without cheats.