Not in new construction building, best way to find out is to call Plumbing inspector to the job site and ask him. An inspector has a right to do an exception to the code, if there is a very good reason.
Plumbing yourself is not a great idea doing without any knowledge of codes.
That would depend on where your located on the planet as some areas have no plumbing codes
Same type of materials used in all types of plumbing EXCEPT plastics in most civilized codes
The plumbing and sanitary codes and violations of them, are not established as felony offenses.
Certainly hope not as each state / city /town has their own codes
When the local codes allow its use on the piping as some codes do restrict the use of tape
The science of plumbing has changed trmendously. Plumbing codes have been developed not only to provide safety in home but to meet the needs of the Fire Services Department.
City Data and Dreamtown both have a map of Chicago with zip codes. Zip Codes itself also has a website that shows all the zip codes on a map of Chicago.
2" by most plumbing codes
By plumbing codes, no.
Before you take on any major projects, check your local plumbing codes. The Complete Guide to Home Plumbing Plumbing 1-2-3: Install, Upgrade, Repair, and Maintain Your Home's Plumbing System Basic Plumbing Advanced Plumbing: Pro Tips and Simple Steps Popular Mechanics Plumbing & Heating Plumbing : Basic, Intermediate & Advanced Projects Home Plumbing Projects
That would depend on which side of the planet your on as some areas have no plumbing codes thus no degree or HS is required