Your link didn’t work so I can’t look at your specific pattern. There may be some reason they called for dpns throughout, but I usually start beanies on a 16" circular and move to dpns at the top. Sometimes I switch to 2 circulars (add a second one of the same diameter, of any length). If there are not enough stitches to begin on the 16" needle the designer may have liked dpns best as her method of choice to solve that issue. There are others as zkimom pointed out. But her statement
So when most people use circular needles for knitting, they use the Magic Loop technique which allows you to use a larger circular needle than you would normally use for a circular project.
is a good point of discussion, I’d have to say I doubt a real study has been done on how many people prefer ML. I know I don’t. Too fiddly for me, you spend half your time pulling the needles through so you can use them (exaggeration)
Anyway there are several ways to knit on a small circumference, it sounds like the designer of your hat may prefer dpns, but it can be done other ways.
I liked your statement and question:
Also, the pattern calls for "stockinette stitch (knit all rounds). I was under the impression that stockinette was 1 knit row, 1 perl row*
If I knit in the round, does garter stitch automatically turn into stockinette?
Yes, it automatically turns into stockinette. I prefer to call it magically. :lol: Knitting is full of mysteries.