Will/gonna/present continuous

Hi.
Is it that if we're inviting people to our organized party, 1 week prior to the party we say we will have a party next week, 2 days later we say, we are gonna have a party, and, 1 days before the party day, we say, we are having a party tomorrow?

I mean when exactly to use present progressive instead if gonna, and they both instead of shall/will?

Thanks in advance!