Re: 2 x line-ins and 2 x headphone outs?
Hmm. I always distrust set-ups like this if you opt for a 'no mixing board' approach, just because you'll be dealing with different levels on the lines. For such a simple set-up, I would suggest a little Behringer mixer (sub-$80) and adding a small headphone amp. ART makes a small headphone amp like the box you pictured that I bought for $50. So, a small investment, but you'll have separate control of all the line levels, which I think is the best solution.