I listened again, especially focusing on the HF end after what you said, and I have a more detailed suggestions for things I'd try (note that doesn't mean they'd necessarily work!) if I was mixing this:

I think on both tracks the voice could do with a little more top end for clarity. Having done that, it could be reduced in level. Especially on the mandolin song, I though the voice was a bit over the top when it came in. With more HF on the voice, and maybe a little less on the mandolin which is a very bright instrument, you could get the voice level down without losing clarity of words.

On the guitar song, the balance between the voice and guitar varies, and I think what's happening is the voice is naturally quieter on the low notes - I'd try gentle compression on the voice so it sits more evenly just over the guitar level. But first, record with a mic on the guitar!

Anahata