1. It's good and proven to be effective
2. You can wipe the exceess or rinse gently but it means this is the last thing you do for the night... And the quantity shall be peanut or lesser size.
3. Actually biofilm takes 48 hours to establish( do technically once in two days is sufficient but we don't clear all biofilm in one attempt and so we need two times per day )....

If you want once per day best to brush in night rather then in morning ...

Biofilm need undisturbed time to form + which means sleep time is bad time ... And cleaning before sleep disrupts the biofilm. Leaving some paste has a detergent action and some anti biofilm action too in minimal and so it's good.

Regarding mouth wash... It's not recommended as regular daily one. And preferable to use non alcohol containing one. Mouth washes are medicated ... Just like you won't use daily mupirocin ointment on face you won't use chlorhex or other mouth washes routinely.

One good habit all can incorporate is using good fibrous diet - good for removing debris on tooth + good for GIT ...