Re: Typekit, a little more detail:
You can still make changes to your Typekit fonts but only via the Typekit.com website — like before. Purchasing the upgrade would give you access to the visual font preview and chooser tools, so you can apply the fonts right from your WP.com dashboard.
If you choose to stay as you are you’ll be grandfathered in forever.
The two-week window mentioned relates to the “Kit ID” that ties your account to Typekit. If you want to change that later you’d need to upgrade, but you can leave it as is if you’re happy with your fonts and don’t mind managing them on Typekit.com.
As to the two blogs you mention, they are using different themes, and thus look different. One is using the Connections theme, and the other is using the Contempt theme.
You can easily change that by visiting Appearance → Themes on one (or both) blog's dashboard.