I said I touched on this subject, I don't think it would be a problem for you to create your own kekkei genkai, after all it's a fanfic. I believe that people will accept it if the creation process makes sense. It's no different than creating the original jutsus themselves.
While Fujin and Hiruzen kept talking and while Fujin is lazily thinking about Kekkei Genkai there are 134 Orphans just standing there and staring at him lol!
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I hope that Fujin is able to learn Senjutsu & use it as a medium to perfect:-
(1) Hiruko's Kekkei-Genkai technique
(2) Body Revival Technique
(3) Zero-Tails
Fujin should also find Ryumaku Vein & create his own version of Ryumaku Chakra Control to have access to almost unlimited Chakra.