Mona has independent roots: Italian — short form of Madonna ("my lady"); Irish Muadhnait — "noble"; Arabic munā (منى) — "wishes, desires." The Mona Lisa — Leonardo da Vinci's c. Mona Charen — American political commentator.
Mona does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Mona reduce to 7, The Seeker. This is a traditional interpretive system, not a factual claim about the name.