Vaiva is from the Lithuanian vaivorykštė (rainbow) — short form. Vaiva Aplinskaitė — Lithuanian Olympic figure skater. Vaiva Babickaitė — Lithuanian sculptor. Vaiva Genytė — Lithuanian author. Princess Vaiva — Lithuanian royal heritage naming. Vaivorykštė — the iconic Lithuanian word for rainbow appears throughout Lithuanian folk songs (dainos), often as a symbol of feminine beauty and natural wonder.
Vaiva 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 Vaiva reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.