1) as far as the topic is concerned, comes is the singular third person form of the present tense; Will come is the simple future tense; Coming is a present participle and belongs to a non-predicate verb; Be coming is a progressive tense. Changing the auxiliary verb Be into corresponding forms can form the present continuous tense, past continuous tense, future continuous tense and past future continuous tense.

2) The following four sentences mean:

He will come tomorrow to show that he will come tomorrow (or will come tomorrow), which belongs to the pure future tense;

He will come tomorrow to show that he will come tomorrow, which belongs to the future behavior that is being prepared with instant verbs;

He will come tomorrow to show that he will definitely come tomorrow, and he uses the present tense to show future behavior that will not change;

His coming tomorrow means that he may come.