Bird in hand.
The absolute best case scenario for the Cardinals would be for Murray to come back and play well down the stretch but for the team to end up with #1 and #2. Team at #3 now has to think that they will get jumped by other teams in the top 5 and miss out on BOTH QBs so they trade #3 and two additional first round picks and probably two second round picks as well. Once the #2 pick is on the clock, the Cardinals could conceivably have the exact same scenario.
The team at #4 is scared that they will miss out on QB #2 and they trade up offering #4 and two additional first round picks and likely two second round picks.
The Cardinals then take MHJ at #3 and the next best player (Alt? Fashanu? Verse?) at #4, while sitting in a position that they will have a plethora of picks of the next two seasons to build a team around. This could also include trades for young stars on their rookie contract as well.