Is HRE x Chibitalia considered Yaoi?

Sort of but I would really go with no because in chibitalia HRE thought chibitalia was a girl and kissed him but it's not like their having u know what but its only because he was mistaken for a girl and it's not like HRE is upset because he was a boy I mean it's not chibtalias fault or even HRE fault I don't blame anyone even hidekaz for adding the scene in.

As long as it is two males,whether or not they know the other person is male or female,it is still yaoi. .3.

No. IDK why, it just makes sense.

Well, technically it's a slash pairing, but it's easier for me to see it as straight than slash. HRE fell for Chibitalia thinking that she/he was a girl, not a boy, so not that HRE is psychologically homo nor he intended it to be a homo romance.
BTW, did HRE find out that Chibitalia was a boy?