You already have a border on the pieced blocks. Trim them to the same size and then trim the one-piece blocks to that size, also. Even if you have to cut 1/2 inch off some of them, that doesn't seem like a lot of waste or a big deal. Go for it.
Happy quilting.

My quarter inch foot is worth a MILLION DOLLARS to me.

I had 20 blocks sewn by different members of a guild and they were ALL different sizes. The quickest way to go forward is to set them on points with triangles attached on all four sides. What I thought was humorous is that I ended up selling all those quilt tops at the Guild's craft show. Here is a picture to give you an ideal. We all make mistakes, so just start making lemonade !! :)

I'm wondering what you mean by "scrappy". To me it means made of many different colors (as in scraps) and can be anything from squares to intricate patterns. IHMO, these are the most beautiful quilts of all. if anything, imperfect piecing would be less obvious in his type of quilt.

We all have one of those "where's the 1/4 inch line" quilts in our history. Don't despair, but do get a 1/4 inch foot.