Definitely, especially if you use the disposal to get rid of food waste!
Everything for a normal install should be included, however there can be exceptions. As with everything, the universal fit, one size fits all, sometimes doesn't. Garbage disposal, most use the same mount to underside of sink. Usually just a matter of loosening and removing existing and installing replacement. Different brand or size may require the drainage pipes to be configured a little different then current install.
The disposal under sink mounts are generally the same or similar and many times existing can be used. Usually requires loosening 3 screws on mount, then use screwdriver as a lever to twist , unscrew the old disposal from mount. Re-install in reverse. Included instructions are generally pretty clear about this step.
Believe there will be a plug if there was not a dishwasher connect previously.
Yes you can pour boiling water down the drain. In fact, this is recommended when pouring grease into the drain. Run hot water for several minutes to make sure the grease gets all the way past your house plumbing and into the main sewer before hardening. But NEVER use hot water while running the garbage disposal! Only use COLD water while the unit is running, per manufacturer recommendations.
This kit is comes with 1 1/2 " fittings. These fittings and connectors in the kit are not schedule 40. You may be able to possibly use a rubber coupling with clamps for your application.
Yes this will work if attach the trap directly to (E). Not every part needs to be used with this kit but it has the parts for many installations options.
Nope.
Plumbers tape
Yes