1) Patronize your local stores whenever possible; you might pay a premium up front, but you will make that money back in service after the sale.
2) Some names are synonymous with quality, others not so much. Remember, you're paying for the name too, and for some names, you pay a premium. In the final analysis, buy the best instrument that you can afford, and let your ears and hands guide you in the decision; don't get so attached to a particular name/model that it blinds you to the most important consideration: how it sounds and feels to you to play. If you find an instrument that you love to play, you'll play it more and progress that much faster.
As to your questions: Dreadnought, classic, jumbo refers to body size/style. Each manufacturer has their own nomenclature. Larger sized bodies enhance lower frequencies of sound, and hence sound "fuller" than the smaller styles. It's a balancing act to find a tone you find pleasing in a guitar size that is comfortable to hold and play.
A western guitar generally has some sort of "western" (american) gimcracks associated with it; fret markers, headstock decorations, etc. It also probably has a smaller body and shorter neck than a "standard" acoustic (whatever that may be).
Woods, I'll leave to others.
If you're not planning to play through an amp, then a straight acoustic will get you more guitar for the money; you don't have to pay for the electronics too.
I personally find that the width of the nut, which dictates string spacing on the fretboard, affects my playing more than anything else. If you have fat fingers, you might want a wider neck. By the time the strings get to the right hand, the spacing seems less critical to me. I also finger pick, plus I'm working on hybrid (pick and fingers), and I've never run across a good guitar that I felt cramped my right hand style.
I don't find any downside to a cutaway, but my ears may be less critical than others. I like the ease of access to the upper frets that the cutaway provides, and I notice only minor differences in tone in similar models from the same manufacturer.
Check the neck relief and the height of the action at the body fret. On a decent guitar, fret at the 1st and 12th fret, and look for daylight under the 7th. You should see it, but only just. Look for string height (above the top of the fret) at the body fret to be around 1/16th of an inch. My archtops have no fret buzz with an action height of 3/64ths; I'm basing off of that.
You recognize the proper action by feel, and lack of fret noise. If it seems stiff, then the action is probably too high; if the frets buzz, it's too low.
Play something you're comfortable with, and play the same piece on every guitar you consider. Look at the finish work on the guitar: feel for uneven or projecting edges of frets along the fretboard, look at the neck/body joint, sight along the neck for obvious bows and twists. Check the body at the bridge mounting, look for evidence of the bridge pulling away. Look inside the guitar, check that the kerfing is even. Check the nut, the strings shouldn't be buried. Look for cracks or runs in the finish.
Detune the guitar a bit, and then tune the string back up to tone (particularly the G string), and listen for a 'ping' at the nut. If you hear it, then the nut is binding the string, and the string is under uneven tension over it's length; it likely won't stay in tune well.
No information on your 'pop.' Doesn't seem right, though.
Strings are personal preference all the way. Experiment and find some you like. Try getting a different sort of strings each time you change, until you find the one that sounds best to you, or the ones that seem to hold tone the longest.
Ovation necks seem to be too narrow for my taste. Other than that, go with what feels good.
Good luck, and let us know what you get!
"There's such a fine line between genius and stupidity."
--David St. Hubbins
