Diving into modals

characteristics | social interaction | politeness principle | politeness test | intercultural |
Grammatical characteristics (how they differ from verbs in general)
no verb agreement
He swims but He can swim.
*He cans swim.
never followed by to or a verb with -ing or -ed/-en
I want to swim, I am swimming, I have swum but
I can swim, *I can to swim, *I can swimming, *I can swum.
can not follow to have -ing or -ed/-en ending
*I want to can swim. *To can swim is wonderful. *After canning swim, he went home. *He is canning swim. *He has canned swim.
can not be used with do to form questions or negatives
He does not swim. Does he swim? but
*He does not can swim. *Does he can swim?
the past tense form usually signals present or future activity rather than past
He might swim this afternoon. *He might swim yesterday.
He should swim this afternoon. *He should swim yesterday.
are always the first auxiliary before the verb. Can not be combined with another modal.
He may have been swimming. *He have may been swimming.
*He may can swim. *He might could do it.

Some suggest that the following are modals. Do they fit all of these criteria?
better, best, dare, need, ought to, have to (hafta), going to (gonna),