The Father is also clearly named Jehovah (YHWH) in scripture (even Israelite personal names show this) but no one else ever is - Is. 64:8 ("But now, O Jehovah, thou art our Father; we are the clay, and thou our potter; and we all are the work of thy hand." - ASV.)
Some Israelite personal names: 'Abijah,' (9 persons found in Scripture with this personal name) means "The Father is Jehovah." 'Joab' means "Jehovah is the Father" (3 persons, at least, in Scripture).
There is no other person called Jehovah in plain terms (as in Is. 64:8 above) or in the meaning of the many Israelite names. There is no "Jehovah is the Son." There is no "Jehovah is the Messiah." There is no "Jehovah is the Only-begotten." There is no "Jehovah is the Firstborn."
'Jehovah is the Father' only.