1 - Yes, you can use the module position parameter in a custom recipe. e.g: return "right-metamod";

2 - No, there are no tricks (or problems) in upgrading from 1.5 to 2.0. All of your current PHP recipes and other parameters will remain, and will continue to work in the same way. HOWEVER - don't uninstall MetaMod first, just load the new one over top of the old one, else all your existing MetaMods will be deleted.

3 - There's a new version of the plugin which you should upgrade to as well. Using the old plugin won't break anything, but will prevent you from using some of the new features.

-- to download the latest version of the plugin (assuming you have already purchased MetaMod Pro), go to http://www.metamodpro.com/shop/account, log in, and click on "view" next to your order. Scroll down to find the download link.

So you need to install both the MetaMod 2 module, and the MetaMod Pro plugin. Both of them just install over the top of the old versions - don't uninstall the MetaMod module first or you will lose your old modules.

Hope that helps,
Stephen