Answer: A trap plug or trap union is for cleaning the trap, NOT the drain line behind it.

Yes, but ideally we avoid it if possible to prevent messy drain cables and machines inside your home. Also, this method may not work if the piping arrangement has too many turns before the blockage, making the cable strength ineffective.

Easier to locate the sewer line. It makes clogs accessible to proper-size blades and cables. Enables access by Hydro Jet if needed. It's closer to stoppage with fewer turns, giving cable added strength for better clearing.

We do NOT go through roof vents. This is a very effective way to cause roof leaks but an ineffective way of clearing stopped drains. Drain vents use non-directional fittings which are different than actual drain lines. Very often this results in trapped cables. It is unnecessarily dangerous and we don't want anybody getting harmed.