I looked it up and found the raw dialogue of chapter 202.The kanji used in Endeavor's speech about Touya's power, was 火力 which is FIRE power and Endeavor actually does say Touya had more fire power than him. Endeavor was not speaking in general terms. He specifically said Touya had a fire power.
So, despite the picture of him showing white hair, Touya possessed something from both parents - Fire from his father and white hair and weakness from his mother. I guess if Shouto can have fire powers there is no reason at least one of his siblings couldn't have them too.
I looked it up and found the raw dialogue of chapter 202.The kanji used in Endeavor's speech about Touya's power, was 火力 which is FIRE power and Endeavor actually does say Touya had more fire power than him. Endeavor was not speaking in general terms. He specifically said Touya had a fire power.
So, despite the picture of him showing white hair, Touya possessed something from both parents - Fire from his father and white hair and weakness from his mother. I guess if Shouto can have fire powers there is no reason at least one of his siblings couldn't have them too.