I may be wrong here, but I'm actually pretty sure that if you mark 'No Interest' on a high need role, there's NO chance of you getting it! But by doing so, you might decrease your chances of acceptance. I marked 'No Interest' for nearly every single high need role (QSFB/Custodial/Housekeeping), except for Lifeguard. I was asked about Lifeguarding during my PI and actually explicitly said I'm not a very confident swimmer and felt other candidates would probably be better suited for the role than me, and I was accepted for Merch in the second wave. I'm actually an alum, and I'm pretty sure I also marked 'No Interest' for high need roles on my first program. So you definitely 100% can do this and still be accepted. QSFB/Custodial/Housekeeping may be high need roles, but roles like Attractions and Merch also take a lot of applicants, so if you mark these kinds of roles high, I think your odds are still good. In my exp. if you're planning to mark high need roles w/ no interest, it also helps to apply early when applications first drop. Obviously the longer you wait, the more Merch/Attractions/etc. roles are filled. I applied on the day of app drop both times.
That being said, I think showing a willingness to work QSFB/Custodial/Housekeeping/Lifeguard definitely helps your chances of acceptance, since the DCP is always super intent on filling these roles. If you're completely confident in your resume, experience and interview skills, feel free to mark 'No Interest' for all of these roles, but I would say it's safer to mark at least 'Low' on one or two. You can always express your lack of interest in these roles during your PI, as long as you're diplomatic about it. But of course if you do mark 'Low Interest,' Disney has the right to place you in that role, whether you want it or not.
Overall, I want to say marking 'No Interest' on high need roles doesn't necessarily hurt your chances...But marking 'High/Medium Interest' in these roles definitely HELPS your chances, so...you have to weigh the odds, if that makes sense.