I would restart. If they're indoors with low light, they've probably become etiolated and are very difficult to recover at that point.

With cucumbers and squash, it's easiest to start them outdoors, in the ground in a spot that gets at least 6 hours of direct sunlight. I've found cucumbers grow better in the fall here because the heat quickly makes them go bitter in the late spring to summer. What I do with squash and, to an extent, cucumbers is plant 3-4 seeds spread about 6-12" apart in a spot that's at least 3' square, and then cut out 1-2 plants that take a little longer to grow. This gives them plenty of room for roots. Initially, I water them every 2 days, then spread that out to about 2 times a week after about 4 weeks. (How much you should water depends on what type of soil they're in) After they're about 3-4 weeks old, I put mulch down around them. I also start fertilizing them with a lighter-than-normal fertilizer, but more frequently than on the instructions. I've had big yields from just 2 plants doing this.

I don't understand why the seeds aren't going directly into the ground, mulched. With this weather they'll even be a week or two faster maturing that way.

If you still have some, put them outside under cover for a few days then set them so they get morning sun and late morning shade for a few days. Then early afternoon sun [now depends on your garden when it goes into shade this time of year and if you use shade cloth] for a few days. Keep that soil moist and don't let it dry out now it is outside. Then transplant them. The idea is to harden the transplants off. Alternatively, harden off in the spot they are transplanted into. (link below) Plants grown indoors need to adjust to the outdoors. Plants grown from seed outdoors will have a thicker and waxier leaf surface to help retain water.

This assumes the transplants weren't rootbound.

Here is a link that might be useful: AZMGM on transplants