There's no need to remove the mulch. It's organic matter also.

The weed fabric might be blocking the organic matter from helping the soil. I'd probably remove it.

I am new at this and learning more everyday. I just purchased Mike Mcgrath's compost book and getting some good basic understanding but have alot to learn.

So I will remove the weed fabric.Should I work the compost in along with the existing mulch or just lay compost on top and walk away?

I think either way will work.

Mother Nature lets the leaves fall and then walks away. The new ones do not get worked down in with the old ones unless a passing pig smells a truffle.

One more ? since the compost is mostly from leaves,and for my arborvites,weeping cherry tree etc. would the ph from the compost be ok. I am not sure if these shrubs are more acid or more akaline. Or does this not matter?