I would put my money on hive because the flood dont have access to the ascendant realm or hive magic.

Hard to say, flood are next to impossible to wipeout, they are basically a thinking parasite or virus that is constantly adapting. However they do require food in the form of organic matter, and it is hard to say whether or not they could actually consume and control hive bodies. From most of what we have seen the hive after death are almost like empty husks, they just fall apart and turn to dust, basically. Which would make it very hard if not impossible for thw flood the consume and use dead hive as they would dead humans. So it is hard to say. If the flood can consume and use dead hive, then i would say the flood wins, simply because taking out an ever adapting and rapidly multiplying parasite is basically impossible. Remember it took basically wiping out all organic life and needing to restart life itself in order to stop the flood, those are some extreme measures. However if the flood cannot consume and use hive bodies, then they are basically done for, they would have no food supply and so they could not do things like multiply, nor use their main method of adapting. This one key question basically determines who would win and who would lose.

The flood. They consume everything and they don’t need a leader like the hive.

The ewoks.

The basic Hive? From my knowledge, they were strong, but hardly a match for the Flood. But, if you factor in the ability to Take then things get a bit more complicated. I’d still say Flood, since too my knowledge only Oryx could Take.

<Against the Hive on their own? The Flood. But with the power to Take I wouldn't be so sure.>

Might wanna change the tag to #gaming. You’d get more answers there. Also The Flood will always win.