A combination of Fridge Horror and Brilliance, Lovecraft stated that he'd been trying to warn everyone about the Voice from the beginning, and though his team rightfully points out he should have just flat out told them, during the party he was telling the history of the house to Linkara in such a way that it was clear the house was dangerous, only to be taken lightly in spite of Linkara's own experiences with Cosmic Horrors. Considering who invited them all, it's no wonder this didn't set off warning bells.
The Voice, an unthinkable horror from an otherworldly dimension, is seeking to inhabit an Earthly host body. Naturally, the first one it chooses is H.P. Lovecraft.
Linkara doesn't care about losing the security deposit because, even though it's his name on the papers, Hagan was the one paying for it, so he isn't out any money on it.
If Linkara had been upfront about just wanting to throw a party and invited everyone normally, they would have not only had more people attend, but would have likely had more superpowers on their side, like Angry Joe.
