I really like the mitts - and I'm thrilled about the site, thank you for the link! I'm considering knitting a "Rogue" hoodie for myself.. I bet the aran silk tweed would be really nice for it. How does the wool feel to the touch when it's knit up?
I like a tighter ply, too - I usually hold one single fairly straight while plying, letting the other one run into the ply at an angle, so it winds a little round the first single. Just play with different ways of holding the singles while plying. And don't be too scared of overplying - if the singles aren't really freshly spun, the ply will kink up anyway, but it'll get sorted while bathing the yarn. If you think your ply is really way overplyed, check how the individual fibres are aligned (easier to see in multicolour wool) - they should be mostly parallel to the plied yarn. A little off is okay, but if it's off by too much, the yarn is either seriously over- or underplied.
As long as she communicates well with her swap partner, too, and it doesn't take too long for her to complete the swap, I'd still give her positive feedback. When I have a swap partner that let's me wait for the package due to personal reasons but talks to me about it, I'm pretty understanding. Life can simply get in the way, for me good communication is the key to resolving these issues.