Have you thought about contacting someone like Email Monks? They can create LPs to be very user friendly if you sent them an example of what you're looking for, and they're cheap with a quick turn around.
Are you trying to make this a self serve page for less techie marketers?
If so, use tokenization. Plenty of articles here on that.
Can you include a screenshot of what you're trying to setup, I might be able to help you with something if I could see what you're after here.
Are you looking to be able to have people edit the divs from within the Marketo Landing Page Editor? If so, and if that's not working for you, you may have "nested" editable areas where one editable container is inside of another. This (and other) errors will usually get caught if you use the "Validate Syntax" tool in the LP Template Editor. If you open up your template (you should see a bunch of code), this will be a tab in the top left corner.
If you're not trying to make these changes to the code (on the template-level) and instead trying to add HTML into an Editable Area in the LP Editor (not the template editor), you'll also probably run into a problem trying to make editable areas that way - those need to be declared on the template. Here's a link to the Marketo Docs on setting that up: Create a Guided Landing Page Template - Marketo Docs - Product Documentation -- I use the "mktoText" option the most, that'll allow you to put lots of different types of content into an editable area (not just text), and that's what I'd use for a "leaderboard" style editable area like you described.
Hope some of this helps ya, let me know if you've got any more specific questions - Im happy to post a little code to help get you going.