RE: Bringing the ultimate Defi to Hive-Engine???

If you build it, they'll come. Hard to offer 0.3% of fees if Hive-engine doesn't charge fees, but like you say, incentivising will be up to the project managers.
I've spent the last week trying to wrap my head around uniswap, and I think enough has percolated through the layers of Simpsons quotes and ex-girlfriend's birthdays that I kinda get it; and it's an incredible concept.