Griz
Welcome to the forum! You'll be able to find all kinds of info and support on here.
On the popcorn issue, I'd say no...you can't have it. First of, on induction you should only be eating the foods that are on the acceptable foods list. No others! If you're past induction I don't think it's a very good choice....especially the microwave kind.
The box I have shows 15gm of carb, 3 gms fiber....doesn't mention the sugars. So that would give a "countable" carb of 12gms of carb! On induction you're only allowed 20 gms/day....do you really want to use up almost all your carbs in one sitting? The simple carbs, the sugars are listed sometimes, but it's only the fiber you subtract. The other carbs are complex carbohydrates, which is broken down to sugar before being absorbed. Fiber is not absorbed, so you don't need to count it.
Dr Atkins does list air-popped with butter as an acceptable snack for children, but they are better able to control their insulin levels. Maybe at maintenance you could have it? The fat in microwave popcorn, my box anyway, is not "good" fat. The list on mine includes partially hydrogenated soybean oil, sucralose and milk ingredients. Air popped, with butter a "real" fat, is much better for you!
The glycemic index (GI) is a measurement of how fast the sugars are absorbed. the faster they are absorbed (high glycemic index) the more likely the food is to cause an insulin spike. the GI of pop-corn is 79 (according to a web-site I found) and carrots are 70. We are not allowed carrots on iduction because of the high glycemic index. When choosing carbs, even once on maintenance, you would be better to pick the low glycemic foods as they are less likely to cause an insulin spike.
For ideas about how to cook low carb, there is a recipe thread on the forum....take a look and see what's there! I'm like you, I can get into eating the same few foods over several days....and I'm not very adventurous in trying new recipes.
Hope this helps some. I'll let someone else tackle the other questions you have.
And again....welcome!