Will this sink piping configuration result in standing water in the pipe?

I recently had a contractor put in a new sink and disposal along with the piping. The disposal tailpipe is just barely above the drain pipe, however the p trap doesn't go straight out.

1. Is there a minimum height requirement that the disposal tailpipe must be above the drain?
2. Does the p trap need to be straight out to the drain or can there be an additional elbow like in the picture?
3. Does the dishwasher drain (smaller plastic tube) need to be above the disposal, or does that get pumped in without the need for gravity?

Thank you for the help!