Some people think the pine needles are going to be too acid to add to the compost or use as a mulch. I haven’t found that to be the case. The process of composting with all of the other ingredients and everything getting all mixed together almost always ends with a nearly neutral pH. Toss them in. As a mulch they don’t raise the pH an appreciable level, you could not apply enough and they take too long to break down for them to change the chemical make up of the soil. Pile them on. As for things that will grow in the permanent shade, try epimediums, Euphorbia amygdaloides var. robbiae or the native Pachysandra procumbens.