It sounds like you know more about this than me, but I've never had any troubles using AK Connect with my SS other than gapless playback does not function. Out of habit, I do clean up the tags when I buy a new hi res FLAC album so only the most necessary info is retained.
In regards to the remote, AK used to make a simple bluetooth remote that retailed for about $50. Perhaps they still offer it—I would call iriver directly to see if they still have any in stock.
Alternatively, I have a friend who bought one long time ago for his 240 but he now uses AK Connect. He probably would be interested in selling it. Message me if you like.
I'm actually not too fond of the idea of carrying an additional remote. After all, the 240 is a "portable" device.
Just a question, when you're using AK Connect on the go, does your album art show up properly? Just wanted to confirm if it's the embedded album art tag is causing the crackling.