Interchanges are usually 1 move. Like in [R U' R' , D] (UFL to FDR to LDF). If you're talking about the insertion, which is 3 moves in a pure commutator, it works in the same way, but since there's no way to get DBR to UBR in 3 moves without affecting any D layer pieces other than DBR, you can't...
What are the advantages of using DFR instead of something on the top other than R2? Seems kind of bad to be honest. Maybe because they like DF for edges and want them to be adjacent?
For timer starts, do I have to have everything that is on the timer my fingers, or can I just have a tiny bit of fingers with palm on the timer so I could get a good cube pickup?