Do you find flat picking minimizes pick noise?

I'm not sure what you are asking. Flatpicking is playing the guitar using a flat pick. All picks are flat. So you would have pick noise because you are using a pick. Did you mean to ask about the use of a "thumb pick" or "finger picks" as opposed to a "flat pick?" Or are you perhaps referring to fingerpicking?

Either way, it has been my experience that you can reduce pick noiceby using either a thicker pick, or by experimenting with picks made out of different materials. I sometimes use a pick made from a clear acrylic material. I forget the name of it, but it has a much softer tone than a regular pick. Also, Dunlop "Tortex" picks should give a better tone than regular celluloid picks.

using a pick IS flatpicking....and usually flatpicking tends to make music you would use a claw or finger technique on sound brighter. When we play with our fingers, unless we have long fingernails, the strings, especially metal stings, can sound muted..but playing something intended for claw/finger style with a pick makes it brighter and more clear.

The only way I know of to clean up pick noise on an acoustic is to have good form, learn the sweet spot on a pick for gripping it correctly, with just enough pick to strike a string without muting it, but being able to mute it with your thumb should you want to, or pinch the string for an artificial harmonic or whatever.

IF you meant downstroking or downpicking compared to alternate picking, I would say downpicking only can sound a little cleaner, but it also is choppier compared to alternate picking which can flow better, and allow for more speed.

No. I thought flatpicking was the use of a pick/plectrum, as opposed to finger picking. It certainly gives more crisp notes, and I enjoy it.