how are disguise and deception used in this play?

Really this play relies on disguise and deception to further the plot. Shakespeare utilized a lot of this in his comedies. You are correct in that disguise and deception allow for various couples to get together. In this misinterpretation of people there is much comedy and drama to be mined. John spreads lies about Hero,Beatrice and Benedict spy on each other and misinterpret what they here, Hero pretends to be dead, there is a masked party....the list goes on.