Best part of your post, imo.
This, however, I disagree with. If you can imagine that the Altaria is the Swablu's mother, can't that be the message? Following that school of thought, the next logical conclusion is that maybe the fakemon is an adopted sibling, or a close friend that's been invited to fly. There's so much you can interpret from that drawing! I mean, the emotional message is already there regardless of a background. Yes, backgrounds help, but I believe if you can't identify the emotional message or empathize with the piece-- that's the viewer's problem, not the artist's. [Not trying to be argumentative, you made a totally valid and very respectable post!]
Anyway, outfox, this particular piece does tell a story to me, moreover because you've included your own Pokemon in there. I feel like there's something very nurturing about the Altaria because you choose to draw a fakemon. I mean, if I had drawn it, I would have thrown a Pikachu or Bagon in place of your fakemon. Which totally makes sense if you know the characters-- but falls flat on the imaginative side. You, on the other hand, you've added something that's completely your own to tell the story. I admire that a lot!
I like your teacup bird! It reminds me of Majora's Mask, tbh. c: I want to see you really plug that detail beyond the people/animals in your work. Get into that cup/gravy boat (lmao) and give it character! There's so much by way of design and shading that you can include. Make it dilapidated and old, or elegant and ostentatious! The naturally surreal nature of your characters can be elaborated on so much with a touch of realism in the right places. That, to me, will make this piece and subsequently your gallery, more believable overall.
Ugh, sorry, I'm not trying to tell you what to do. :x
In this case, a "landscape" background may not be necessary. Like dbp said, a splash of color [something subtle, watercolor-y, and abstract-- like what you did with this piece only directly behind the pokemon] might be just enough to make them stand out yet still give body to the work as a whole.
This was a wonderful update and I think for a lot of us here a place of really great conversation! Thank you for inspiring us once again outfox! n_n; Can't wait to see more!