I like this a lot.  It seems like a very reasonable intermediate step between Chess and Chu Shogi with a focus on the Lion.  In fact, I can't think of any way to make it a more reasonable intermediate step.

I like the choice of crowned rook and bishop rather than chancellor and archbishop.  As you mention, the latter don't occur in Chess or Shogi, and may be too powerful. (Actually, I think a Capablanca-type 10x8 game might well be better with crowned rook (dragon king) and crowned bishop (dragon horse) than with chancellors and archbishops.)

I also like the fact that the king, queen, crowned rook, crowned bishop, and commoners are all 'lion-proof' in the sense that they can't get igui captured because there is no safe adjacent square.  This might eliminate my concern about the lion's ability of baroque capture walking all over the 'normal' chess pieces (although I'd certainly still be testing that notion the first time I played the game...)

Castling - I'm assuming the king moves three squares left or right and the rook jumps over to the adjacent square.

Pawn Promotion - I like promotion at the 8th rank.  It not only invokes the promotion of Grand Chess, which the layout of this game reminds one of, but also of the deep promotion zone of (Chu) Shogi.  The real question is the promotion rule...  I see a few ways you could go.

Grand Chess style - promotion optional at 8th and 9th rank, mandatory at 10th, but only can promote to a captured piece for which it is replaced.  This has a certain elegance to it, and would be really nice for over-the-board play (if you happened to be using a set specifically designed for Chu Chess.)  On the other hand, it's not really like Chess or Chu Shogi, so it might not be a good choice on that basis alone.

Chess style - promotion to any non-pawn piece (knight, bishop, rook, crowned bishop, crowned rook, commoner, queen, lion.)  Obviously promotion to some of these types is probably pointless.  If you went this way, would it even be optional at 8th rank?  Would you ever really want to delay this decision badly enough to keep it a pawn?

Shogi style - promotion to a single type only.  I agree that to commoner is probably too weak.  Maybe promotion to a crowned rook?  If I had to pick a single piece that would probably be my choice.

Progressive style - this is what I did in Cataclysm, and for that game I like it, but it is neither chess-like nor shogi-like so I'm not really recommending it, but mentioning it for the purpose of completeness.  You could, for example, at 8th rank, optionally promote to commoner or remain a pawn.  At 9th rank, optionally to crowned rook or crowned bishop or remain a pawn.  At 10th rank you must promote to queen or lion.  Has the virtue of giving incentive both for promoting and for delaying.