There isn’t an exact science on how many mentees to invite. It’d be nice if we could say for every ten invites, you usually see seven applications, but we haven’t found it to necessarily be that prescriptive.
It’s best to invite more than you can accept if possible. This will allow for some to choose not to apply or for you to be selective if not everyone is not a fit. But if you do that, it’s important to set the expectation ahead of time that applying doesn’t necessarily mean they will be selected.
If they aren’t chosen, the answer is usually isn’t no, but rather not yet. Plus, having a waitlist for your next season isn’t a bad thing at all!