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That's pretty good; it has all the important stats. You could definitely keep it and use it personally, although I wouldn't anticipate a high trade demand if that's your purpose.
With a lot of calcs on various 'mons I've found that 30 and 31 amount to the same OHKO odds. Not sure if this is the case once you add Soul Dew into the mix, however.
I think the 2nd one is probably better, but yeah they're both great.
I dunno, it's borderline for a 5-IV and decent for a 6-IV. You could keep it, but it's not amazing and so wouldn't be great trade leverage. Up to you and your patience.
That's good enough. Not great (and some finicky people might not be eager to trade for it), but definitely good enough for use. So it's up to you and your patience/obsessiveness.