Read the entire FAQhttp://wiki.linuxmce.org/index.php/FAQ
LinuxMCE uses MythTV for recording. There isn't a "clean" way to import recordings that I have found - you need to be comfortable editing databases using SQL and have some understanding of how MythTV is put together. I have done this before using the directions from the MythTV website, but it's been a while. Basically, you back up the recordings and metadata tables from the database, move the recording files to the new hardware or place in the file system (LinuxMCE uses a very specific file system organization that you must conform to - see FAQ), import the database, update the file paths, and install MythTV. Then, MythTV takes care of updating the MythTV database schema to the latest version, and LinuxMCE takes care of setting up the tuner cards and listing sources. I'm not sure what version of MythTV you are using, but it should be less than or equal to LinuxMCE's current version (0.22-fixes) for this process to work.
LinuxMCE is not compatible with MythDora - you must install Kubuntu 0810, and then install LinuxMCE on top of that.
Most of your hardware looks fine. The only thing that stands out is the CommandIR IR transceiver - I don't believe LinuxMCE has a device template for that, and adding it is probably not trivial. The most popular and best supported IR transceiver device is the USB-UIRT.
Search the forums and wiki for the ION board you have - there may be special setup considerations.