These look more like slight edits and recolours (which are kinda taboo here) if existing Yoshi sprites than Pokemon sprites. I would suggest making a custom (or at least edited) larger Yoshi sprite.
Well...Even though I resent edits and recolors, I really do think they can work if you edit a sprite beyond recognition. The problem here is that the instant I see these sprites, I know where you got them from (Yoshi's Island DS, SMW, Yoshi's Island).
As a start, why not put down some of your own lineart and try improving from there?
well I didn't actually copy and paste the sprites and just change the colour
I couldn't find some of the sprites sheets from some of the games (smw, yoshi island, DS ) so what i did was start from scratch by using some images that were found on the internet that were a bit faded (not sprites sheets as they didnt show up) and just recreated them using paint.
I also felt that some of the sprites used fitted in the art style of the game (smw and smw 2:yoshi island) as those games were released around a year or a couple of years before the first pokemon games came out in Japan.
I guess I should of put no copyright infringement intended on my sprite sheet though.
While I understand you didn't copy and edit, you still used existing sprites and recreated them then recoloured them. Like DDP said they just look like blatant copies of official Yoshi sprites. I still think that it would be nice if you tried to create your own Yoshi sprite or edit one (like DDP said) beyond recognition.