Low Fermentation Temperature

I think everything is OK, but I need some reassurance. I brewed a cream ale on Friday and used WLP080 Cream Ale Yeast Blend (65F-70F). This is the second time I've used this recipe but the first time I used the yeast. I was concerned about fermenting at too high of a temperature so I put my fermenter into a large cooler with two frozen (1G) milk jugs.

I pitched at 72 and walked away. I started to get bubbles in the airlock fairly soon. A few hours later, when I checked the temp, it was 58! I pulled out a jug and the temp eventually got to 60. I pulled the other jug last night.

This morning, the temp is 64. I feel that the two days at a lower than optimal temperature won't hurt the flavor, just slow down the process. Is that right?

On a related note, I am pretty pleased with how the cooler and ice jug worked. Maybe I should use 2L bottles next time.

You are correct, I also have had problems with too low of an initial fermentation temp on a few ales and weizens. This lower temp didn't hurt the flavor too drastically, but it did take significantly longer to ferment down to final gravity. I should think you are safe.

If you want someone to tell you it'll be fine, no one knows yet. It'll be beer. It'll most likely be fine, but you may have lower attenuation than you might've. Looks like you got through the lag phase while it was warmish, and so there's a concern that you may get a sluggish fermentation, maybe get some of the yeast to drop out. 14° drop in "a few hours" is pretty hard. If you just saw a few bubbles for some reason and it was still mostly aerobic I'd bet you're fine. I've purposely retarded the lag phase on big beers by pitching at 56 and letting it freerise up to temp with good results.