a-Is there a difference between:
1-If you don't build a fence around your garden, your neighbor will come into your garden.
2-If you don't build a fence around your garden, your neighbor will be coming into your garden.
(I think 1 could be used instead of 2, but if the action of coming into the garden will take place only once, then only 1 can be used, 2 necessarily implying repetition.)
I see no meaningful difference between the two sentences. Also, "will be coming" does not, without additional information, imply repetition.