Satchonsims and pixelade have got to play this game early on youtube.

I watched SatchonSims' build video. I like how it looks, but since it's multiplayer, I'm just not interested in this one.

So on their Steam forums there are some answers to obvious questions :

Q: so in the latest vid i watched about multiplayer is this game only just about building or will their be other vivaland npcs too romance instead of romancing your friend?
A: There will also be NPCs in the early access of the game!

Q: Will there be modsupport?
A: Coming from a team who are mod supporters, we would love to make this possible in the future!

So, npc's will be added at some point and no actual confirmation of mod support in that answer. The described active careers on the store page are very minimal. They talk about romance, but without npc's yet, its romancing the people you play with in multiplayer :/
I don't think npc's or mods can be an afterthought in a sims like game. So, imo this does not look like a sims alternative.

I'm sure the bolded part won't get all kinds of messy. Yikes!

Eww, Nope!