You can apply a lot more force with a pipe wrench than a channelock. Tearing down a 50+ year old 3/4 system with pliers sounds like a nightmare
Don't forget the Sawzall!
Pipe wrenches and adjustables are some of the most overabundant tools in the world.
for pipe wrenches, The HF aluminum is usually good enough and way lighter than steel, and there are more Al options at the box store. If I made my living plumbing I'd be sure to buy some.
The thing is, 98% of the people who own or have ever owned a pipe wrench will not use it enough to wear it out. I have some from the 20's and 30's that are in about the same condition as my Ridgid I spent $130 on a few years ago(good with some paint flaws and tarnish spots). as a result, you can go to most any flea market, yard sale, etc, and get about any size you need for 2-15$ except for 36 and 48"ers which have intrinsic value. The jaw teeth should be sharp with no chunks broken off, and the handle straight, easy stuff to check. Ebay kind of ***** here , because shipping tends to double the price.
A big adjustable is key as it won't mark up the cosmetic fittings which can be pretty large.
the Channellock was an appropriate choice, you will find very few plumbers without a few.