Dragonite Most important stat

everything else being equal,probably number 1, dragonite's att is so high 2 points are negligible.

they are essentially equal though, i would look more at lvl and dust requirements.

Evolve them first. Then choose movesets to power up. But basically every Dragonite with IVs above 82% is worth powering up.

The first option is best since it would add max bonus onto Dragonite's def and sta base stats. Padding onto his attack stat is negligible since it's already the highest one.

If you use GamePress' CP calculator, the Dragonites at level 30 with those IVs will be
1) 3015cp, 144hp
2) 3023cp, 144hp

1 might take a little less damage depending on rounding, and 2 might deal a little more damage depending on rounding. Not that big of a difference either way. Choose one to evolve, and you still have a good backup if the first gets a bad moveset.