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 o even HRE fault I don't blame anyone even hidekaz for adding the scene in.

As long as it is two males,whether o not they know the other person is male o 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?