What is significance of the two intrigues by Mirabell and Mr. Fainall? How are they linked with the final scene of the play?

God, this play is sooo cool! You should definitely read this! Or see this! That's gonna be kinda a spoiler if I tell you, so, please, just read it. Believe me, it's worth it! By the way, I write about different cool things for young people on http://www.youngupstarts.com/2018/08/17/adv-developing-science-through-dissertation-writing/. Hope, you're gonna like it and you'll find something useful for yourself there! Good luck!