She rejects all types of pedialyte, ors etc. can i mix pedialyte with water and add formula milk to develop milk like taste and give her?what 2 do?

Yes you can: But why are you giving your child pedialyte? Is she dehydrated? Is she vomiting and can't keep anything down? If this is the case and if severely dehydrated, she needs fluid replacement, preferably IV. But if she drinks milk and keeps it down, no need to force something she doesn't want, most important is replacement, milk is safe. If in doubt see her doctor again, best wishes