It says "have sims chatting at the same time 0/3" and "have sims dance at the same time 0/3".
When my sim is chatting with another sim, the 0/3 changes to 1/3 and it's still 1/3 when there are more sims chatting together. It's the same with the dancing where it just has 1/3.
I've also tried inviting other fans to dance to see if I can achieve the dancing goal but the other sims don't respond.
Are the other sims NPCs or members of your sim's household?
I generally play large households and for events and parties, I find it much easier to complete goals like that using household sims that I can control directly rather than the NPC invitees. So, if your sim has other household members, you can try doing those goals that way. If you are playing single sims though, that won't work. Though for the Meet and Greet, I've found that the celebrity sim who scheduled the party has to personally complete some of the goals like the one to have 3 drinks.
Hope this helps.
