Let's break this down and analyze bitch by bitch.
Lily - Most likely she pledged just to have parties and fun. Her Pink Rose side job should earn her a lot of money and she should not have to worry about tuition, although more money is good and she have no qualms about it. Quinn accepted her because she is HOT material and a good addition to her menu.
Ashley - No idea why she joins. For fun? To attract Derek's attention? Quinn accepts her because she wants to expand and thought she can persuade Ashley?
Maya - Definitely for the free tuition. Quinn sees through her and is trying to break her to either join or quit if she cannot add her to the menu.
Josy - For free tuition and for Maya. Quinn only accepts her because she is Tommy's step sister to spite Tommy. It's evident when Quinn only batted her eye when Josy mentioned her relationship to Tommy.
Mona - For fun? Only at the pool scene she said she's in after she found out about the tuition. Agreed with your assessment on Quinn's plan for her.
Camila - For fun? Agreed with your assessment on Quinn's plan for her.
Quinn is desperate, that's why she's eager to expand and adds them to the menu immediately. It's bad business planning. She should take economics class with Jill.
Normally one would not give higher access to secret operations unless you're proven your worth by climbing and gain Soldato ranks. Even Soldato rank members are not giving confidential information on how some of the operation runs.
I largely agree, but a few thoughts.
Lily probably joined the HOTs because Tommy and the other DIKs said she should and she figured it would be fun. Quinn might consider her a shoe in for the restaurant, but then again, Lily might not see any need to let Quinn call the shots when she can do the same work with a lot more autonomy back at the Pink Rose.
Ashley specifically said she joined the HOTs because she saw Maya join them and she respected Maya's judgement. Why Quinn would accept her as a pledge is unclear, since they were already accepting 4 daughters and there's little reason to think Ashley is restaurant material.
The only thing that occurs to me is that maybe Quinn wants to drive up the daughter count because it makes it easier to get Sage on board with fundraising activities that Quinn can try to piggyback off of (as she barely did with the ANO party). In the long term it will cause all sort of problems; as Heather notes the house will be crowded and their contributions should cover their expenses. But in the short term it might create a sea of red ink to help motivate Sage, and we've seen that Quinn has a rather myopic perspective.
As for giving away secrets, the only daughters who are clearly know about the restaurant are Camila and Mona, and none of them definitely know about Quinn's drug dealing. It seems like Quinn misjudged Mona's limits, but it remains to be seen if Mona will consider spilling the beans.
Then again, it's not like Quinn's ring is a well kept secret. She told the MC about it after knowing him for all of 20 minutes. He might be a DIK pledge, but that's flimsy proof he is up for prostitution. At the end of the day, this always seems to come back to Quinn being pretty bad at her job.