This turned out really cute, but the broken-rib pattern throughout makes this one take a little more time to complete. It kept me interested, though, so it was worth it - I get bored with too much stockinette. It also hides any inconsistencies with stitch tension so it was very stress-free.

MODS:
Working this as a seamless design.

Cast on 113 sts. I didn’t do any decreasing after the bottom rib was complete.
Divide underarms (WS): Patt 26 sts, bind off 4 sts, patt, 53 sts, bind off 4 sts, patt 26 sts.
Sleeves: Cast on 34 sts and join to work in the round. Inc to 35 sts on first round after cuff at the EOR; from then on, I always purled that extra stitch on every round in hopes of creating a faux-seam of sorts. Inc to 45 sts; cast off 5 sts at ‘underarm’ on last round before joining to the yoke. (Make sure the last round of the sleeve at this point corresponds to same row of the pattern that the body has at that point. That way, the broken-rib pattern works continuously across the yoke.)
Yoke: I worked central-double-dec’s at the raglan seams.
Buttonband: I left live stitches when the yoke was done; for the fronts, though, I picked up 3 out of every 4 row. I also included a yo at the ‘angle’ above the buttons, which then got worked as a kfb on the following row as well. I made only 4 buttonholes - they are every 10th st apart. Next time, I’d make the body a little bit longer - otherwise the FO fits great!