I have a home made garden hose/copper tube CFC at 25' and it works well.I do mostly the same. Except I don't bother capping the ends between batches - just let it drain. Sanitize w/hot wort before the cooling water is turned on. That wort gets collected & goes back into the kettle.
IMO there is no issue with the cd break going into the primary, the beer is still great and crystal clear when packaged.
I have no pump either and the CFC is faster when the ground water is colder obviously.
As for cleaning and sanitizing, when done chilling I flush with boiling water, use an air gun to blow out the moisture and cap the ends.
Prior to chilling I spray star San in it. When ready to chill I hook it up, let some of the boiling wort pass through into a separate vessel, then turn on the cold water and go to primary. I lose maybe a cup or two of wort but this method has served me well with no issues or infections
Don't need a pump, the tubing is long enough that it goes from boiling to pitchable temperature as it drains. I go straight from the kettle through the CFC into the fermenter. (My ambient water is in the 50's pretty much year round.)