oatmeal and mashed potatoes on pureed diet

As long as it is on your list of permissible foods, don't worry about it.  You'll only be eating a little bit, and only for a short period of time.  Once your stomach is healed and you get the OK for regular food, then you will want to limit or eliminate the oatmeal and mashed potatoes.  Mashed potatoes with beef or chicken broth as "gravy" were one of my favorites for those first few days.

I personally never bothered pureeing regular food like steak.  Heard too many horror stories from nurses about people who had bypass surgery and tried to puree steak and ended up with obstructions.  Now maybe it was only for bypass patients, and maybe they just weren't using their blenders correctly, but I'm a worry-wart.

I didn't have an official puree stage with my plan. After 10 days of liquids it was open season. My NUT said I could do cream of wheat when I was a few weeks out. I just chose not to. I wanted to focus on the protein and no way that was going to happen if I was putting oatmeal down there. Plus, I am a carb fiend. I didn't want to jump in with high carb foods so early.

Different surgeons have different plans and different expected goals for their patients.  If your goals are in line with your surgeon's goals and you are following their proven program that consistently leads to the agreed upon goals...there is no problem.

If you are asking this, you are not sure if following this plan is ideal for you.  I can tell you that I would not have eaten either food during the weight loss time.  There are plenty of low carb alternatives to eat and my doctor would have clobbered me (not really, but figuratively) if I so much as had apple sauce during weight loss.  He was focused on getting me to 100%EWL and so was I.  We agreed with each other on our goals and our methods.  You need to ask your doctor what are his goals for you.  If you agree, excellent, if you disagree, think about doing something that leads to what you want in most patients.  That's my best advice.  You run this show, this is your journey, do what gets you to your goals.