It's pretty hard to "take too much off" a yew :-) They are one of the few conifers that can be cut to the ground and regrow from just the stump. I don't suggest you do that - the cold damage seems to be superficial and relegated to only the ends of the top growth - but you should feel free to remove as much damaged foliage as you wish.

if we look only to that which is actually budding ... you are not going to have much left ... i suspect whatever does not bud out.. might brown completely in the heat of summer ...

its always helpful to know where you are ...

is there any chance.. that what was covered by snow.. is budding.. and that which was not is the part not budding out???

the brick might be part of the problem.. if it was gathering and retaining heat .. and the plant or the roots were going in and out of dormancy in the dead of winter ...

ken

Yes, it probably burned to the snow line - and will do it again the next time the same conditions occur.