Yes you can run phone with data with cat5. there are 4 twisted pairs in a cat5 and cat6. You would only need 1 pair for phone. leaving 3 pairs for video or internet (data). I would use blue or brown for phone and leave green and orange for data or video as they are more twisted and less prone to interference, especially over long distances.
This is without question the worst advice I have seen on AVS. Seriously, don't ever repeat this advice.
Yes, you only need two pairs for 10/100, but there is a reason why Cat5/6 cable is not referred to as "structured media cable for cheap folks", and that is because 4-pair cable is designed to be run and terminated in such a way as to preserve its data carrying capacity.
According to Cat-5 5e or 6, the un-twisted part of the wires CANNOT exceed 1/2". When you start dismembering cables so that you can connect to two jacks, you will expose about 1.5" minimum, and the wire will no longer be able to carry 100MBs. Yes, you can get around it by properly terminating both ends, then creating a franken-connector to plug into it and split the wire pairs.
So you spend a few hours drilling holes and then decide that running two cables, at $.10/foot, is too expensive? That you would rather create a useless, hobbled network?
And for the rest of us, Cat5 is useful for thermostats and remotes, not networks. Please do not give network advice unless you actually understand networking. Gigabit ethernet is incredibly useful, and easy to impair if you think of Cat6 as just little-bitty versions of speaker wire.