1. Are they playing soccer this weekend?
2. Will they play soccer this weekend?
3. Are they going to play soccer this weekend?
[Is #1 grammatical? Are the three all the same in meaning?]
4. I am meeting the girl this evening.
5. I will meet the girl this evening.
6. I am going to meet the girl this evening.
[Is #4 grammatical? Are the three all the same in meaning?]