After my toddler heals do i need to get all the neosporin cream (neomycin and polymyxin b) entirely off?

Yes: I don't know what your toddler is healing from, but prolonged contact to the neomycin in the neosporin can lead to allergic reactions in the future. So, yes, removing any unneeded cream is a good idea as is using it sparingly to begin with. Plain vaseline or aquaphor will often help heal wounds as well as neosporin without any risk and is what i recommend to my patients post skin surgery.