Whilst I think holding onto Robinson is a very viable option for the Knicks, his salary could be better spent elsewhere. Hence why they acquire Vanderbilt to start at PF and Richards on a friendlier contract than Robinson to be the backup center (although Robinson could start next to KAT).
DEPTH:
PG: Brunson/McBride/Payne
SG: Bridges/Kolek/Shamet
SF: Anunoby/Hart
PF: Vanderbilt/Achiuwa/Morris
C: Towns/Richards/Sims
The Lakers lack center depth. They can experiment with AD at the 4 next to Robinson, or Robinson can help take the load off an injury AD throughout the season. They also get off Vincent's contract and clear some salary.
DEPTH:
PG: Russell/Hood-Schifino/James
SG: Reaves/Christie/Curry
SF: James/Reddish/Knecht
PF: Hachimura/Wood/Lewis
C: Davis/Robinson/Hayes
The Hornets are in a position to acquire picks in exchange for taking on salary. Here they gain a second round pick and a young guy for someone who is supposedly available for trade.