Baby Romper Troubles

I’m having trouble starting this romper. Is the pattern incomplete, or am I missing something?
I have co 104sts for size 3-6mths (using fingering weight). I tried the alternate cable co multiple times to end up using the long tail because I couldn’t get the buttonholes to k2tog yo with the 10 stitches from the middle (always landed on a purl). I’d like to slip the first stitch, but when I do, I lose a stitch in the next row. How is this harder than it should be?! :confounded: Thanks in advance.

The written pattern is here:

That looks like a really nice pattern for a very sweet romper.
You should be able to place the buttonholes as you like with either k2tog yo or p2tog yo.
Slipping the stitch shouldn’t cause the loss of a stitch. It should be just moving the stitch from the left needle to the right. Is it possible that there’s another cause for the loss of a stitch? If this is in the k2p2 rib section it should be fairly easy to locate the missing stitch. Is it a missing yarn over in the buttonhole row?

Placing markers is often helpful in keeping track of stitch number and looking for missing sts. Every 10 sts would work.