We're not actually turning into a mindflayer despite the tadpole, so what exactly is the problem with multiple tadpoles? It's not like we can suddenly turn into multiple mindflayers.
(Yes, I'm definitely going to try a playthrough where I take the 'pole power route. Probably with a fiend warlock, to fit the theme of ideas that trade short term rewards for questionable long term consequences)
Obviously you're not going to outright die or turn into a mindflayer (maybe you do temporarily), but you're probably going to end up confronting some of your companions with lethal outcomes or getting mind controlled by the tadpole on some decisions, preventing you from reaching certain outcomes on the main story, meeting certain characters or the option to befriend them, etc.
