yeah i would probably switch malady and bloodrazor around, otherwise pretty good

First thing I wanna say, you dont need magic reg runes for Teemo, there's better suited runes than that. I also think getting a level of Move Quick early game, maybe at lvl 4 isnt a bad idea, it puts you faster than all the other champs and lets you move around to plant mushrooms<- thats what Teemo's do right?

Anyways, about the build. Getting Bloodrazor with no atk speed back up is probably going to make you waste your mid game trying to build it up. Teemo's good at farming, but getting 2 expensive items right off the bat wouldnt be smart. Probably with your build, Madreds should be a late game tech in for the champs you mentioned. The items needed to build up Bloodrazor isnt good either, its not the same as Ashe having a BF sword with her as she builds up her Infinity.