Tracy~you should be able to tolerate the 'instant' versions without a problem just make it a little loser than normal...I just wouldn't get any flavors with fruit since it's dried and could be an issue early on (after your 6 weeks of low residue it shouldn't be a problem). Instant versions are well rolled to make them that way and it's not as bad as the kind you have to cook on the stove top.
Crunch Berries were my favorite right after surgery!! Love them:)
Keep a log and try things...like you said we are all different! Personally, I eat everything, without issues. To get to this point I tried all foods in small quantities and chewed well...If it didn't bother me I ate it again(and again!!). Just introduce one new food at a time so you know how your body reacts.
You will find that you may not have to drink all your liquids...once you vary your diet you will see that you get a lot of fluid from other forms...and you will slow down/thicken your output, too.
During your 6 weeks you can eat veggies in a can like green beans (don't try corn or peas yet) and peaches or pears (no fruit cocktail yet) in the containers are okay for most. Give pasta a try, just cook it a minute or two longer than the box says. You should be able to eat a cheeseburger now just don't put any veggies, pickles or onions on it yet! Chicken Nuggets should be okay, too, just don't try a salad until the 6 weeks are up and when you do try something like Boston Lettuce that isn't very rough.
A lot of foods come out the way they go in...it's not going to cause any harm...if it bothers you, don't look too close