For Najaran, he probably won't be able to sense anything in card form, so that should be simple enough.

Spark/Gar/Privateer Pirate is where it gets complicated. If it's the same person in three different forms, Ryo is eventually going to be able to tell they're the same - the more he interacts with any of them, the more he'll become familiar with how they feel through his Sense, and it wouldn't take him too long to cotton on to the fact that they feel the same. ICly, if asked, he will absolutely keep the secret; if him knowing at all is an issue on an OOC level, we'll definitely need to figure something out.