I can't find anything for a EVGA Q3. They have a BQ line, and a B3 line, but not Q3 as far as I can tell.
550W would probably be fine for that build unless you're doing extreme overclocking. Under torture test 7700K should draw somewhere around 100-150W, 1080 maybe 200-250W. If you say 50W for everything else, that still leaves you with ~100W of headroom. Although bumping up to a 600/650W wouldn't hurt.