For these particular sentences, the first and second would be more usual in L1 usage. The 'will' form (Future simple) seems slightly more formal than the present continuous form. The 'going to' form seems slightly unnatural - it's not really an intention, more a fact.
In general, present continuous for future is used for fixed scheduled appointments or diary commitments - 'I'm visiting the dentist on Tuesday.' (I don't necessarily want to go, but there it is, in my diary, so that's where'll I'll be.)
The 'going to' form is used for talking about what you intend or hope to do ('I'm going to wear my black jacket at the party.') It's also used with predictions about the future with evidence 'Look at those clouds. It's going to rain.' or 'I feel strange. I think I'm going to be sick.')
The 'will' form is most often used - for predictions after 'I think' - 'I think our team will win tomorrow.' - or in first conditional sentences 'If I see him, I'll tell him'.
- or in more formal written forms 'The conference will be held in November.'
It's quite a complex area, though!
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