I just have a Harbor Freight clicky torque wrench. Works fine for me. My opinion, you only really need to get within +-10% of the specified torque values in most automotive applications. Any brand of wrench will get you there if you treat it right and don't abuse it. Looks like that tekton torque wrench will be fine for what you need. I'm pretty sure I have that exact set of adapters you linked, and they work great.
I find a good sturdy ratchet and a rubber mallet is enough for breaking everything under the car free. I wound up needing an impact driver and associated bits for removing wheels. Saves a TON of time over a breaker bar/tireiron, and you don't need to stop the wheels from turning.
As for tightening drain plugs, I just tighten until it's firm with a regular ratchet. If it doesn't leak, and you can get it off again...
Edit:. Oh! And a magnet on a stick. You don't realize how important it is until you need it. Like I just found out today... Not really necessary for oil changes and such, but you will need it one day.