He's not going to Freo, not the least because his manager is Young. Wouldnt be surprised if that Twomey tweet was the first time Brockman heard of that 4 year offer. Dont mind Freo and Hawks shaking hands to work together to avoid getting a raw deal though (even if I personally think a future 3rd is pretty fair from WC).
Problem for the Hawks there is only WC and Brockman (and his manager) need to agree to terms (which they seem to already have) for the move to happen. Benefits of being shithouse I suppose.
As you've said, unless Bell and Young can somehow get on the same page, which imagine would involve significant $$ overs, he ain't going to Freo