Example: Correct: I will be eating pizza soon.

Incorrect: I will be eatting pizza soon. (We don't double 't' when adding -ing)
Incorrect: I will eat pizza soon. (We have to use future continuous)

1) We will be meeting her tomorrow.
Tomorrow we will her be meeting.
We be will meeting her tomorrow.

2) It will probably be raining when I will reach London.
It will probably be raining when I reach London.
It will probably have be raining when I reach London.

3) Today at eight I will be writing a test.
Today at eight I have written a test.
Today at eight I will be writting a test.

4) They will be discussing problems at 9.30 tomorrow.
They be discussing problems at 9.30 tomorrow.
They will discuss problems at 9.30 tomorrow.