I’ve never applied to incubators and am wondering a few things:

• Do applicants typically keep only one “active” application at a time to reduce the number of times their ideas are exposed? In other words, apply to one incubator and do not apply to another until you’re rejected/haven’t heard back about the most recent application. This is in contrast to sending applications to a number of incubators all at once.
• When you submit an application to an incubator, does the incubator actually shop your proposal around before doing an initial 30-minute interview? Or do they do the initial interview after only one person decides you’re proposal is interesting enough? I’m sure this varies. I guess I’m asking if there’s a common practice.
• Is it pretty common to get a request for an initial interview? In other words, do incubators only follow up on stellar ideas or do they also follow up on mediocre ideas? Again, I’m sure this varies. I’m asking if there’s a common practice.

For context, I’m transitioning out of graduate school. I sent applications to two incubators and got requests for a 30-minute call for both. A few weeks after my first interview, I was rejected. I haven’t done the second interview yet. Honestly, I didn’t expect to get any responses to my applications so I’m wondering if these incubators actually saw value in my proposals or if it’s just standard practice for them to always do a 30-minute interview.