CalDAV/CardDAV: For N900 sync'ing, syncevolution, for Android sync'ing, DavDroid. It creates local accounts that can be used with native Contacts and Calendars. It's free and open source, get it from https://f-droid.org/

Any MCE remote (search on eBay) are as cheap as chips and should work great. I use them on my XBMC boxen.