Different LiPo brand

Is It possible to drive with two different LiPo Brands as long the mAh is correct?

This will boil down to how much do you want to keep your LiPo batteries in good shape as well as wanting to mitigate any potential, though small, possibility of problems for your ESC. Even among the same line of batteries there may be enough deviation in the cells to cause some premature damage. This is why balancing the cells from time to time is so important. Because having a cell deviate will eventually snowball and kill that cell. This ofcourse becomes greater when working with batteries that aren't manufactured to the same spec or tolerances.

Long story short, if your care about your batteries it's smart to pair like batteries. If you don't worry about longevity, as long as the cell count, "C" rating and capacity (mAh) match....you can technically use them together.

Everything X said was on point.

I personally start with pairs of batteries for my savage and use any widowed batteries for other trucks that only need a single pack.

Stay the same

Thanks for good information.