Final notes about Oscar Wilde?

I think you have all the answers, you just outlined them! Only using those small parts of the play and the preface? Well the preface clearly uses what some may consider "misapplied logic" and many contradictions and paradoxes. The play makes fun of conventions for sure, but I dont remember any specific pages. The ending of Ernest when Jack finds out his identity is definitely an example of "misunderstandings conicidences and revelations" don't you think? Good luck on your test!