First, regarding pockets: The coat is entirely knit in garter stitch. Can I add on a pocket if I wanted to in garter stitch, too, or does it have to be stockinette? If I wanted to do a fair isle design or intarsia on the pocket, can this be done in garter stitch, or will it look weird?

My next question is that I've made the baby size Einstein coat three times, and all three times, the third buttonhole came out placed very close to the second one. It looks kind of awkward. I can rework the pattern I'm sure so that this doesn't happen, but I would have to really sit down and figure this out. The picture in Sally Melville's book doesn't show this flaw, so I'm wondering...is it something I'm not doing right? Has anybody else made this coat and has this problem with it? I made a rough illustration of this problem; it's the two buttons I colored in.

Knitting a garter stitch pocket would blend in better than one in stockinette, but it will be more likely to sag if the pocket is for actual use.

If you want to do intarsia or fair isle, I'd suggest stockinette only because then the design will be more prominent. It all depends on the effect you're after.

Regarding the third button, I'm not sure what you can do. Have you checked for pattern errata or perhaps a KAL somewhere that discusses the problem?