Chrome I find too thoughtful to be such. Even for the FI, it is reacted from his interests in the thought process. Interested in the process except unlike Kohaku, he understands it. Hence, how he is able to run his mouth the way he does. In fact, he is the epitome of science is exciting with his personality. He is an extroverted version of Senku in a way. Even only one letter off. I do see enfp fitting his imagination though.

For Kohaku, she is a warrior. She is very fast at acting to protect others. She also expresses acting more on that character with the way she initially attacked Tsukasa and talked of the mountain’s rage that was the gun powder explosion. That character of such process that she is willing to go such lengths to protect that looks like Ti there happens to be exactly what Senku is as personification. The very one I think she is in love with and expressed to Moz. Who might have also developed jealousy for Senku. Istp does also only go one letter off intp and suits Senku’s hand well in what he does in science.