Is there much of a market in your area right now for priced-up horses that are not yet being ridden (or have only been lightly backed, not actually showable)?
I find that
real hard to believe, and would urge you to be reeeaaaalllly cautions and reality-checking before plunging into this... but, it's your life, plus you obviously are in a better position to know your area than I am
So while I still think the thing is going to be a money pit at best, I will comment on the horses at hand:
First, I do not think conformation should be a major criterion for you. TEMPERAMENT is about 60% of it IMO, much of the remainder being (as someone up above said) "cuteness". Temperament obviously cannot be evaluated from a photo but IMO you are heavily best-off with a well socialized horse who learns fairly rapidly but can take a joke and has no existing bad habits.
#1, who the heck knows from that photo. If he *really* stands like that I'd forget about him but it may be just an awkward moment. His face is moderately cute and he is fine-boned which for some reason is often popular among the set you're apparently pitching to. I can't tell a blessed thing about his conformation, you would need REAL photos or to go see him.
#2, is a plain white app (stroke against him in most places) with an unattractive head (strike two) and quite possibly a traditional appy tail i.e. not too darn much of it (strike three). If you were looking for a horse to keep and use, none of these would matter (although it's also pretty unathletically built and personally I'd pass it by even for myself); but they are the dead OPPOSITE of what you want for resale. You want something of which you can take photos that will make teenagers go "mom, we HAVE to go look at THIS one!".
#3, another semi-useless photo like the first horse's, but it is pretty clear to me that he's a much less cute-appealing horse. Long back, not much hind end I think, long straight low neck, head not set on well, whole big lotta white on face, and a really sour expression. Mind you the expression could just be "a moment", but honestly nothing I see there screams "resale project" to me. If he has a stellar temperament and looks better in person he might be a candidate so if you are bored you might go see him but I would totally not hold my breath.
#4, That is a rather old pic of him, perhaps as a weanling or just-turning-1? Looks very young -- leggy, short-backed, short-necked, not much mane or tail. I would not draw much conclusions about him without a recent pic. Certainly he is the most obvious prospect of the four in the sense of having flashy color and being probably non-ugly. But I was never brilliant at playing "guess what adult horse is lurking inside this weanling" and it has been way to long since my eye has been calibrated on that at *all* for me to want to guess what he looks like now.
Personally I would be going to see all except #2, unless they were more than 20-30 min away in which case I'd bug the seller for much-better pics. TEMPERAMENT is really the single biggest factor here in my opinion, and you don't want to get so stuck on visuals that you pass up a really-saleable personality for a cute butthead.
I still think it's a moneypit though. You want to 'flip' a horse, look for RIDEABLE horses, and expect you may lose money even on them.
JMHO, good luck, have fun,
Pat