I) The Class' icon appears, but is not selectable.
S1) If you are playing Awakening, there is no efficient way around this. Either use the 'spiriteaterx' console command or make a character in the OC and import them in.
S2) If you are playing the Original Campaign, it would seem the Mod's Background files were not installed. Open up the .dazip and manually install the three files within the 'contents\modules\single player\override' folder to your '\bioware\dragon age\modules\single player\override' directory.

I) The Class is selectable, but produces an invisible character whose appearance cannot be edited.
S1) Make sure there is only one 'sys_chargen.ncs' file within your '\bioware\dragon age\packages\core\override' directory.
S2) See S2) above.
S3) Some people experience this issue for no discernable reason. Just use the 'spiriteaterx' console command instead.

I) The 'spiriteaterx' console command turns my character into a Champion.
S) You have some other Mod installed that edits the Champion Specialization. You'll have to figure out which one it is and deal with its conflicting 'cla_data.gda' file.

Q) Will ReSpec Mods work with the new abilities?
A) No. The "runscript removetalent #" and "runscript addtalent #" console commands work fine though. Awakening's ReSpec Tome may or may not work (have not tested).

Q) Where can I find the talent numbers that work with the above commands?
A) The 'abi_base_spiriteater.gda' or 'spiriteater_constants_h.nss' files.

Q) Can I turn an existing character into a Spirit Eater to test it out?
A) Yes. Use the "runscript spiriteaterx" console command.