Option 1 will increase the filter and membrane life of the RO system. Hard water deposits ruin the membrane much faster than soft water.
Potassium soft water is marginally easier on the membrane than regular sodium.
Activated charcoal before the RO also increases the life of the membrane, many...
What it does to the brew is dependent on how much was left in the kettle.
Safety wise, unless you used a full pool shock tablet straight, you're fine. You can safely use up to 1 tsp of bleach per 5 gallons for water purification, boiling will reduce the amount of bleach too. Bleach decomposes...
I've used cheap submersible utility pumps from Home Depot to pump newly dug basements. I've run them continuously for days using a regular water hose with typical head heights of 10-15' without issues. At most, you might need to replace the motor bushings in 10 years. Not bad for ~$50
Superior...