I don't know about the dreams of the personages listed above, but I think not all of them have directly told that they had such-and-such a dream. But from time immemorial, dreams have been a convenient 'device' for our people to do certain things which would otherwise be difficult or troublesome to explain away.
I am aware of one incident. A decaying family in dire financial straits. The elderly man was at a loss to salvage the sinking fortunes of the family. Then he consulted an astrologer, as is normal with most people. The astrologer gave a beautiful plan: make a beautiful stone idol (vigraham) of krishna, secretly immerse it in the centre of the village pond; say that god came to you in your dream and wanted this ancient idol to be resurrected, and so on; to prove your bonafides, offer to meet the expenditure in drying up the pond (with giant pumpsets) till the idol is found/not found. Then claim ownership or family interest in the temple which comes up. Money will flow like river into your purse.
Everything went according to plan. The pumping of the water from the large village tank took some two weeks, since tv had not yet come, the newspapers were full of the news, crowds from far and near came, and when the idol was found at last, the public adulation knew no bounds.
There is now a very good and pucca temple with lot of income, part of which, I understand, benefits the once decrepit family. All god's grace, what else!
Dreams do help, in such cases