Both statements mean the same thing. It is implied that the vines are so full of grapes that the master does not mind that his donkey eats some of them. (See: [[rc://en/ta/man/translate/figs-parallelism]] and [[rc://en/ta/man/translate/figs-explicit]])
Possible meanings for all occurrences of "his" or "he" are 1) they refer to Judah's descendants. Alternate translation: "their ... they" or 2) they refer to the ruler in [Genesis 49:10](./10.md), which may refer to the Messiah.
Both statements mean the same thing. It implies that there are so many grapes that they can wash their clothes in the juice. (See: [[rc://en/ta/man/translate/figs-parallelism]] and [[rc://en/ta/man/translate/figs-explicit]])
Often in prophecy events that will happen in the future are described as something that has already happened in the past. This emphasizes that this event will certainly happen. Alternate translation: "they will wash" or "he will wash" (See: [[rc://en/ta/man/translate/figs-pastforfuture]])