I suggest searching around online or in sewing books for some basic animal patterns that match parts of what Momo looks like...
I.e you could probably use a basic head pattern for a teddy bear for Momo's head and if you can find the ear pattern for a rabbit you'll be set head wise...
other then that you'll just have to use trial and error with making your own pattern...
I suggest getting some cheap material to test out making any areas your unsure of and doing just a loose straight stitch (by hand 'cause it's easier to get out then by machine) to get the general feel, that way if the trial piece works you can just take out the stitch and pin it to the material your actually going to use.
I tend to go with the whole making my own pattern thing because I find it easier, but that's just me... (though I still go around and look at all the patterns I can find both google wish and on Deviantart just to get a general idea of what I should do, 'cause it's not a good idea to anything completely clueless)
Also welcome to the craft forum nice to see another anime fan on here

(I may just have to attempt making a stuffed animal of him myself now that the thoughts in my head... soon as I finish my pile of unfinished projects... I find it hard to stay on one project for too long

)