Not sure about the spots. However, if the leaves are getting fused together, you may have leaf rollers. I get them from time to time on mine and typically don't have to do anything. Sometimes I have had to spray them though.

Yellow leaves and black spots: Sounds like BS, Black Spot disease. Usually roses will get it. Its a spore which lives on the leaf and in the adjacent ground. There are sprays like Funginex and others. Look up black spot disease here or the rose forum. It is a bit of work.

Critters? Yup, they will do that fused leaf trick. Hatch thousands. Take the leaf and burn it in a bucket.

Regarding the oakleaf...do you have deer or any other animals in the area that could be browsing on it? They did that to mine after planting them 4 years ago.
Since then, I have protected the oakleafs with barriers and they seem to have finally gone gangbusters this year, and look so much better/healthier.
If not deer, it could just be a transplant shock/problem. Try leaving it where it's at and maybe give it some mushroom compost and water regularly this season. I have heard that Oakleafs take their time getting going, and I can attest to that. The last 4 years mine looked scraggly and sad. Give it some more time.
I am 99% sure that I have also fed mine Holly Tone, for acid loving plants. That may help too.