i think you can get a pretty good idea of the process based on 3 pieces of information.
1. the bobby wagner isiah pead situation.
2. the comments rgarding mo alexander.
3. snead is still with the rams.
1. if i recall correctly, fisher wanted bobby wagner and snead did some manuevering thinking they could pick up an extra pick and still get wagner but ended up with pead. this tells us that fisher identified players he wanted (likely based on sneads inout) and told snead to go get them.
2. similar situation here. fisher wanted mo. so much in fact they drafted him a bit earlry becasue they didnt have a fifth rounder (something like that). in fact the comments after the draft snead said that fisher suggested he did not want another boby wagner incident.
3. while the rams drafting is not as bad as some imply here, there have been some high profile misses. yet snead is still with the rams. KD is in the draft room. he knows who did what. if he thought snead was a bad evalautaor, i cant imagine KD keeping him.
overall, i suspect it was a collaborative process but ultimately the decision was fishers based on the comments regarding pead and alexnder. now i think snead has a year to prove with worth to mcvay. if not, next year mcvay and kd will search for his replacement.