You should be able to get lots of gold even without these skills. If you have spare skill points you don't know what to do with, they couldn't hurt, and you can also unlearn skills to get the points back (though the price in gold goes up as the square of the character level, so eventually starts getting expensive).
For holy water, I didn't find any for sale until nearly the end of the game (though I was part/half way through before that possibility was added), and had no problem buying one from each of the BF traders.
Trading lets you reduce the price by 6, 12, 18, 24, 30, 36, 42, 48, 54 and 60%, for the first 10 levels.
Embellish increases equipment value by 2, 5, 7, 10, 12, 15, 17, 20, 22 and 25%, also for the first 10 levels.
Beyond Divinity Strategy Guide