The current strategy would be just to take the code exist and convert in the most efficient way that can be implemented in solidity while still holding to the same properties as libzerocoin.
The way that the code is laid out and laying it out the same way and I can foresee that because they are doing it on a different platform, there are certain optimizations that they will be able to make.
For example, the hashing functions.
There is a cheaper form of hashing that is used in solidity and is used by ethereum called keccak256, whereas the Zerocoin protocol uses SHA256, but because we are only converting the coin and using it on another platform, we can make those kinds of optimizations use the more efficient hashing operations which would lead to lower gas costs.
Even given this, there will be some challenges regarding making it work regardless efficiently, but the problem is that he doesn't think that at the moment the given gas cost in solidity, he doesn't think that it would be possible.
But then again, they will try to make it as efficient as they possibly can.