Is this 3-way throuple, like the 3 of them like each other?

Yes it is.

I think? Souichi and Yumeto both have romantic feelings for Yori. As for Yori, he equally loves both.

Its not a true 3P, as in they both only have sex wt Yori and not without him just the both of them, but thats coz they both are in love with him. The sexual attraction for both is just for Yori. But who cares, this is fire!