Who controls Vincent Price's estate?

They are advertising themselves. It might not be the only purpose, but this serves to make the con more interesting to sci-fi/horror fans. It is right and proper they get all the needed permissions.

The OP has not said that the honoring of Price will be a factor in their promotion of the meeting. I believe that the law @Dewey_Finn cited is intended to prevent commercial entities from appropriating the likenesses of celebrities in product advertising, and is highly unlikely to be used to stop (presumably) non-profit fan conventions from recognizing their achievements. If I’m wrong, I’m sure one of our resident legal types will be along to correct me.

The kinds of films Price made were considered pretty ephemeral at the time and nobody bothered to protect the copyright on some.

Are you reading a different thread than the rest of us?

Do you know what being polite gets you?
An email from Victoria Price saying that she is delighted with the idea,and asking when the convention is happening because she comes to Portland occasionally.

That’s awesome! She sounds wonderful.

So very nice to hear.

Politeness for the win! That’s incredible! What a classy lady.

Well done!

Eggsalent to use Mr. Price’s Batman 1966 Catchphrase.