Dianne - give us the link! Want to seeeeeee.
1. I don't remember what gadgets are but my guess is they are the blogger equivalent of applications (apps) or widgets. Wordpress uses widgets.
Let's say they are like widgets...in which case you can choose what to put in your sidebar, like a weather app, a calendar, your categories, Recent Posts, Top Commentators...etc.
Does this sound like what you are looking at? I can give more guesses if this isn't close.
2. When i had a blogger blog i am pretty sure I used affiliate links and adsense. Stick in an affil link and see if it goes through. Let me know if it doesn't work and I can dig into this more for you.
3. When you say lists, do you mean is there an app/form for lists like on Amazon? Or are you asking if that is appropriate for a blog post? if the latter, YES, it's a great idea for a post. Lots of bloggers make lists. I make lists on my blogs. People love lists! if the former, then see the answer to the Widgets question. I bet there is an app for that.