Haha. That sounds adorable. It'll be great. I'm sure she'll grow into the older sister type role eventually, even if it's a bit weird. Get her own little fondness for the weird tree dude and try to help him along.
I think I'm going to try and nap before going out today, but if anything comes to mind feel free to drop me a note! If I'm not braindead by tonight I'll try and work on her then.