Difficult to say, don't really know until you try. The best thing about complete kits of RAM is that they are pre-matched, tested, and guaranteed from factory.
If you set ALL the parameters to the same values most likely yes. You will risk instability if you run them with different timings. Remember there are several parameters to check and set in the bios. Set them all manually including the recommended voltage.
Difficult to say, don't really know until you try. The best thing about complete kits of RAM is that they are pre-matched, tested, and guaranteed from factory.