You can use pretty much any battery technology with OROV, as long as it provides between, say 8 and 15 volts. The vehicle is currently set up with two parallel packs of 3 size 26650 cells in series (this configuration is called 3S2P). Any generic LiCo or LiMn 26650 battery will provide about 11V to the ROV, and thus will work fine.
The reason we recommend the cells that we do is that they have a built-in protection module, that protects against over-current, under-voltage, and also over-voltage while charging. If you decide to use bare cells in your ROV, then you the user have to make sure that none of these conditions occur. Allowing the cells to over-discharge (under-voltage) will ruin the cells, and over-voltage during charging, or having a short-circuit in your wiring which causes an over-current, can lead to a ruptured battery or worse.
So, if you decide to use the cells that you linked, be cautious in all phases of the battery operation.
The TrustFire protected cells that we recommend are not a perfect solution- the protection modules will sometimes trip during hard driving, and the connection between the cell and the protection board is rather fragile- so if you drop the battery or flood the battery tube, you can end up ruining things. Here at OROV HQ we're starting to experiment with some other battery configurations that hopefully will be more rugged.
Hope this helps.