Was any transgender person ever ordained as a Catholic priest?
The short answer is no.
According to the Catholic Church's moral doctrine, homosexual attraction is disordered, and homosexual acts themselves are sinful. However, the Church does allow the ordination of men who may have, in the past, experienced same-sex attraction, but only on the condition that they have lived without engaging in "homosexual culture" or acts for several years, and that have no "deep-seated homosexual tendencies". Priests in the Latin Church are required to live by the Church's teachings, and most make a vow or promise of celibacy.
A 2006 survey suggests that Roman Catholic church-goers in the US were almost evenly split on whether homosexual men should or should not serve as priests or bishops.
A 2000 document from the Congregation for the Doctrine of the Faith concludes that sex-change procedures do not change a person’s sex. "The key point," said the document, "is that the transsexual surgical operation is so superficial and external that it does not change the personality. If the person was a male, he remains male. If she was female, she remains female." However, those who have undergone such a procedure are prevented from ordination or admission to consecrated religious life. - Homosexuality and Roman Catholic priests (Wikipedia)
The Vatican is very clear on this matter:
Consequently, the document instructs bishops never to alter the sex
listed in parish baptismal records and says Catholics who have
undergone "sex-change" procedures are not eligible to marry, be
ordained to the priesthood or enter religious life, according to a
source familiar with the text. - Vatican says 'sex-change' operation does not change person's gender
Nevertheless some breakaway Catholic groups have ordained such persons as seen here and here. These ordinations are invalid in the eyes of the Catholic Church.