At Punk hazzard we saw Law able to use his Power to give animal legs to people as part of cesar's experiments. Why would he not use it to give Kyros a 2nd leg from any of the dead from the event or even have Franky build him a prosthetic, On Franky I understand without the sunny it may have been difficult but if he worked with Law for assembly plus some of the smile factory debris It should have been simple.