active sister

if they know you're a legacy to a good house and dont want you SUPER bad then yes they'll cut you to give girls they think will actually join a chance.

Depends. I know in my house when we were going through PNMs the rush chair would say something like "PNM Jane is from Birmingham, great grades, involved... But her sister is an active in XYZ" and everyone in the room would kind of groan. And keep in mind my house isn't a conventionally "top" house. So yes, some houses, including mine, will drop you right off the bat because they know there's a good likelihood you'll pledge the house your sister is in. Other houses may fight harder for you if you're an overall good PNM. But for the most part, a lot of PNMs pledge the house their sister is in, if they have one that's an active here.

I want to also mention, if you really like a house tell them! If you show interest in them then they'll be more inclined to keep you around longer. It's amazing that you're trying to maximize your options and trying to branch out from what's just familiar to you... However you need to let houses know that's what you plan is. So when you're talking to an active, drop hints that you like them. Obviously don't just say something like "I love you guys, I would love a bid..." I would suggest saying "I was so excited today when I saw this house on my schedule" when an active asks you how your days going/how rush has been going. Or "thanks for everything, I really like this house" while the active is walking you out.