This discussion may contain spoilers!
Im starting to lean towards the possibility of mr. toad being the murderer for the following reasons, hear me out:
in ep.1 we see toad not glamoured and complaining about the price and quality. This is significant because we know the killer has history with using black market glamours on his victims and maybe himself.
when Bigby is questioning Toad jr., tj says he sees someone and mr, toad looks and sounds worried. Tj also hints that he knows more than he is saying but is scared.
Toad is an original character, so anything can be done with him that wont contradict the comics
P.S. this is my first post so apologies if I did anything wrong