Opera Equations Solved

I really had no idea what I was doing creating opera equations, but if you're still in the dark, here are the answers I had in mind.

(Attic - Heat) + 2(Mi) + TB = gelida manina
This wasn't meant to be solved, but it does refer to La boheme's tuburcular Mimi who meets Rodolfo in his cold attic apartment, where he marvels at her cold little hand (gelida manina) to begin a very famous tenor aria.
What's next in this series? 5, 10, 20, 30, 36, ??
The very first words of The Marriage of Figaro find the groom-to-be doing measurements in the bedroom-to-be. He sings "Cinque... dieci.... venti... trenta... trentasei... quarantatre," which translates as: 5, 10, 20, 30, 36, 43
Nemorino + Vino + Time + Jealousy + Second Thoughts = 1 f. l. Solve for f and l.
In The Elixir of Love, Nemorino's been trying to win Adina's heart. He's been drinking wine that he believes to be a love potion, but it still takes some time and the sight of other girls flirting with Nemorino (because they know he's just come into a big inheritance he doesn't know about) before Adina lets her feelings show through. Nemorino realizes he's succeeded when he sees her shed a single furtive tear (una furtiva lagrima) in another of the most famous of tenor arias.
F. = 21; bd of F. = 2/29; therefore, F's had 5bd. Who is F?
Frederic has just turned 21, and his apprenticeship with The Pirates of Penzance is to end on his 21st birthday. However, because his birthday falls on Feb. 29, which only happens during Leap Years, he realizes he's only had five birthdays, which means he has to remain true to his pirate friends and...oh, there's a bunch of Gilbert & Sullivan style implications.
N. needs $; N's X = G.I.N. + 20s. What's s?
Back to The Elixir of Love, a desparing Nemorino (pre furtiva lagrima) needs money to buy more elixir. His rival, Belcore, talks him into joining the army (he becomes a G.I.) which pays a bonus of 20 scudi. The phrase venti scudi is sung back and forth quite a bit. (Oh, and I forgot to mention, Nemorino signs his army contract with an "X.")