'He will come.'
I am certain about his future coming.
He is willing to come in the future.
I insist on his future coming.
He insists on coming as a matter of habit, or on a future occasion.
That's four different possible meanings with just 'will' - no 'would', 'have', or 'if''.
It's impossible to answer your questions briefly when we have just short examples and no context.