Which calculator should I launch first?
Launch first on the page that already gets traffic for the line you most want to write. A calculator works best where a visitor is already thinking about that product, so a busy life insurance page beats a new landing page nobody visits. Prove the lead flow there, then add the next line.
Look at your analytics for the product page with the most visits and the weakest form conversion. That page has interest but no reason to raise a hand; a needs calculator gives the visitor something useful to do before they decide to talk to you.
Browse the calculators by line to match one to that page. Resist launching five at once: one well-placed calculator with a tested workflow teaches you more in a month than five that nobody has checked.