1. It is nice to hear Michael doing his homework.
2. It is nice to hear (that) Michael has done his homework.
3. It will be nice seeing you again.
4. It will be nice to see you again.
Which one/s is/are more proper to use?
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
Can we say ''it is nice to hear Michael to do his homework'' instead of 'iIt is nice to hear Michael doing his homework''?
In #1, you heard sounds, words, or noises of some sort that show he's doing his homework. Perhaps he is practicing for his speech class.
In #2, you have obtained information that the homework is now complete.
It's nice to hear that Michael is doing his homework. -- This might suggest that there was a period in the past when Michael was not doing his homework regularly, and now you have information that he is now routinely doing his homework.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.