You've got a point, that approach might not have worked on a HB8+. Super hot chicks take extra work, but I think it's good to have a few 7's for backup in case the main objectives fail
You can get away with being a bit direct online, it's obvious that you are interested if you're messaging someone on a dating website. In person though, you should never be direct.
When your sister's friends are over, try ignoring them completely. They'll feel that, and start shit testing you with more of that "wtf?" attitude. Don't let them get away with it: neg them! For example, let's say you are talking to your sister (ignoring them), and they say something like "what is this guy doing here?", come back with "get over yourself please. it's not all about you." then before they can respond turn back to your sister and continue talking to her. Don't be too confrontational, just be playful while not taking any of their shit. If you do this right, they'll become interested, and start feeling comfortable around you. At this point you can go into compliance tests, DHV, qualifiers. Your sister WILL try to cockblock you (I have a sister, i know this lol). If your game is good though, this will only make them want you more. Don't invade their space too much, just roll off and let them come to you. Good luck!