Actually, some patterns have you increasing on every row for most of the tow and then every other row for a few more rows - and I like that look better. My feeling is that you keep going until the sharpest part of the toe is done, then go to every other row for the final 3-4 increases.
Also, really the key question is how does it look to you? The main thing to me is that I don't like a pointy toe. If you started with 12 stitches or so, your toe won't be pointy so you should be fine.
I know, not answering your question - but you would find it very rewarding to do things in the round I think! A hat would be a good place to learn.
But to answer your question, this hat, with its pattern, would be more difficult to change into flat than some, but yes, you could do it. Just have to write out (probably) the pattern for the wrong side to make sure you get the design correct.
Without a link to the shrug, it is hard to tell, and you also don't mention how many stitches you have on the needle, but another explanation is a missing comma, i.e., bind off (or cast off) 6 stitches, knit to end, increase in last stitch, 19 stitches - i.e., the 19 stitches tells you how many you have on your needle.
If the shrug is knitted from the front and then you cast on for the sleeves, then it would indeed mean casting on 19 stitches at the end - and to do this you do what I think they call a cable cast on - you put your right needle tip between the last two stitches, pull yarn through and put it on the left needle - and then again put your right needle tip between the last two stitches (the one you already had and the one you just now increased) and again pull yarn through and put it on the left needle - you do that until you have added 19 stitches.
I hope that helps! (But a picture would really help us diagnose!)
it shouldn't be too hard if you have the pattern for the tie. All you would have to do to make the colors diagonal is to move the color over one stitch every right side row. for example, Row 1 would be k2 in A, k2 in B, k2 in A, etc. then on row 3 it would be K1 in A, k2 in B, K2 in A .... and so on. Does that make sense? If you look at it really close you would see where the colors jog over, but you wouldn't from any distance away, it would look smooth.
ounces is the amount of the yarn you are buying in terms of weight - and you will also find it written in grams and often as yards and meters as well. It has nothing to do with the quality of the yarn. In fact, nothing on the label will tell you that. Labels tell you the size (worsted, DK, lace, sport, etc) and the amount (yards, meters, oz., grams) as well as the composition (amount of wool, acrylic, etc. each strand is made up of)
Felting yarn is 100% wool that will felt - felting is like when you throw a woolen sweater in the washer and dryer and it comes out about toddler size from woman size! Felting shrinks wool into a solid piece of fabric that you can cut and everything. Most, or many, 100% wools will felt - unless it is superwash, then it won't. Whites often won't either because of the process they have to go through to become white.
As for your links, the first one is more a chevron than a ripple pattern. The second one is a true ripple - and they are very easy and quick to do and different kinds of yarns give different effects - I've done them with boucle, with fluffy type yarns and with teensy tiny yarns on big needles - lovely every time.
I like the true ripple - the yarn will make it very special, I'm sure, as will the thought behind it. Do make sure it is a machine washable yarn, though! Babies spit up and such a lot!
(Oh, and I'm sure you won't give it to her until she is sure she will be able to carry this precious one to term)