Taking a closer look at your page again, I think I see the real problem.
You've customized the map size in the Geolocation configuration panel, right? The trick is, those values are interpreted as the full CSS values for width and height, not as pixel values.
You put 200 x 200 in that admin panel, which is unitless and resulting in your map being sized 0x0.
Replace each of those values with 200px instead of 200 and you should be fine.
As for the updated theme: it's a little confusing, but you can still do the same customization to the home page even though the file doesn't exist. An index.php, or any other file, will get used out of the theme if it exists, but a default script from application/views/scripts will be used if there's no copy of the file in the theme.
Practical upshot: you can create an index.php in your theme and it will still work the same way, and if you're just looking to see what the "current" index.php looks like, it's at application/views/scripts/index.php.