<< He used white teflon tape at gas connections for water heater, etc >>
Teflon tape is a thread lubricant, not a sealant. Teflon pipe dope or
conventional pipe dope is preferred by many professionals. This has been
discussed to death in this NG...check the archives.
<< He also used no hub connectors off of threaded cast iron nipples out of the
wall and then built his AB >>
Does this guy have a license?
<< Can I run the 5/8" drain hose high from the dishwasher, and drop under the
sink and do my 2' coil under there rather than do it at the dishwasher for the
air gap? >>
Not clear what you're asking here..I'll pass.
<< And finally, is it better to use braided 3/8" water line or soft copper >>
Braided lines appear to be more reliable and easier to install. Your decide.