The tuning won't be exactly the same, as Kalva's aura is 19% vs Fu's 24%, so you'll need to adjust speeds a bit. Also, Kalva is green whereas Fu is red, and on your proposed team you have nobody who is red - so that may be a problem on green affinity, since there's no guarantee the stun won't go on someone who it shouldn't be targeting.

Beyond that, though, sure, the team will work just fine. The only thing I could see being a problem is, Kalva's poisons + extending may push off the DEF down from Fatman, which would seriously reduce your damage. In terms of overall damage output, Kalva has more base ATK, and 3.5x A1 + 8x A2 (not sure exactly how the A3 max-hp scaling works on CB so I'm ignoring it for now) vs Fu's 5x A1 + 7.2x A3 - so, basically the same. But adding the poisons should add significant damage, provided it doesn't cause the DEF down to drop.

So - yeah it should be able to 1-key.