De Ligt and Bentancur for a swap deal would be the only option for me. If only Chellini was young, until the last 2/3years one of the most under rated defenders I can remember.
For a totally crazy swap after reading press recently. We have a player that has a dream to play for Santos and there is a Santos player that has a dream to play for us.
Perreira for Yefferson Soteldo. I remember seeing him at one of the youth world cups probably 4 years or so ago now. To be fair there was another player for Venezuela looked fantastic too that was actually at Watford never heard of since.
Can only judge Soteldo from the tournament several years ago and youtube clips from his time at Santos. One of the smallest players I have ever seen but outrageously talented, was probably the player of the tournament