I live in the southern US, and an expression that you will hear in this region is “might could”. As in, “I might could go to the party tomorrow.” I have also heard “might can” used in a similar way, but it’s less common. I don’t recommend that someone who is learning English use this specific regional phrasing, but it’s worth pointing out that there are regional differences in the language. Another way to phrase the same idea, that should be acceptable in any region is to use the word “maybe” instead of might. Although the location of “maybe” in the sentence might change. And there might be a slight difference in meaning, although they are essentially the same. “We maybe can invite this person” doesn’t sound as good as “Maybe we can invite this person” or even “We can maybe invite this person.”

We might can invite this person as a guest speaker - this is not correct We might need to schedule for another day.- this is correct You could also say "We might have to schedule it for another day" Need to, have to etc are semi modal verbs so often they can be used in ways regular modal verbs can not.

Its also: we might be able to invite him/her or them to be a guest speaker.

I'm from the southern U.S. originally, and people do say "might could." It's not really correct though. As Celena said, 'might be able to,' is the way to go.

You can also say: We may need to schedule it for another day.