You shouldn’t lose any edits. Alyeska is an “older” theme but it was already updated to use the new framework close to a year ago now.
These are all of the themes that will be completely re-done: http://support.themeblvd.com/forums/forum/v1-themes/
Currently Alyeska holds framework v2.1, which needs to be updated to v2.2, but this won’t effect these sorts of customizations we’re talking about here. It’s pretty minor update in the scope of how everything works, or at least in regards to what we’re discussing in this topic.