Yes, I started my seeds too early. Yes, I put them out too early. And yes, as feared, that group of seedlings got all weird and yucky looking after the near frost we had the other night. (I suppose this is as good a time as any to mention that we did not have a true frost, but it did get really chilly... and within 2 days the temperatures were up to near 80 degrees. This is a crazy planet sometimes.)
So, once the temperatures got nice and warm last Saturday (5/18), I went ahead and transplanted the remaining two seedlings outside. Why? Because they were also starting to look weird. Pale. A little yellow. I don't feel very good about their fate. Plus, I know that in attempting to transplant them, I was risking ruination of their delicate little root systems.
So then I decided to just plant a whole row of seeds, in the hopes that some of these might turn into cucumbers. Someday. Fingers crossed.
I found some info here that makes me feel like it's just the weather that is my problem. Even the seedlings on the porch, though it is enclosed, were exposed to colder temps than normal the other night. The ones outside, despite their cozy bedsheet, probably did not stand a chance. The OSU Extension website is a great source of information, especially because it is geared towards my local growing zone.