I let it hydrate for about 10 to 20 minutes. So cold water is better for the yeast? What do you mean by fermentables?
Fermentables would be a sugar source, whether malt, dextrose, or sucrose. I use a few tablespoons of table sugar in my hydration cup, but there are many here who suggest malts like dry malt extract, liquid malt extract, or a bit of a previous grain mash before the hops are added. This allows the yeast to wake up and start feeding, as well as a tiny bit of multiplying.
The best temperature should be between 70* and 90*. In theory. Depending on the yeast. Again, I'm not a purist, and seeing where you are from, it's a lot harder to ferment (and what I do is start a fermentation in the hydration cup) at 60* to 65* where ale yeasts are producing "off" flavors. Higher than 90*, you'll start killing yeast cells. I use colder water only because I'm a little paranoid about it. Also, if the water is too cold, it can warm up, and the yeast will not rouse until a certain temperature is reached.
Using the setup I have, I've seen action within a few minutes of hydration -- that is, when I pour the yeast on top of a sugar solution at whatever the base temperature is of my water pipes. I've never measured that temperature, so I would estimate between 50* and 70*, depending on the season here in Ontario. Sometimes I only let it go for 30 minutes, the last time I "hydrated" for about 3 hours. For each, it still took me a day to see signs of fermentation.
Given that in your picture, I see no signs of krausen at all, and I see no signs of haze at all, I would
assume that there is no fermentation. Granted, assume is a dangerous word, which is why I suggested wait another day. I would still get another yeast packet, and should 72 hours pass from first addition of yeast without any change, then I would use the other package of yeast. This time, *I* would just pour it into the carboy, without any hydration. No issue of temperatures over what the yeast can stand, and you'll have to open the carboy anyway to get the yeast in.