Welcome, mama!
I try to find shoes for ds at Goodwill, so I don't have to worry about the leather issue.
Found him a pair of leather velcro keds in VGC for $1.00.
Also, I have bought him (new) canvas keds and nikes.
I feel bad buying new due to sweat shops, so I try to shop around for used stuff that's in VGC.
Also found canvas baseball keds for ds for $.75 last year at a thrift store. Like new condition, too!!!
No, I don't know of any company that sells vegan kids shoes off the top of my head.
HTH,