Weedy sweet pea seedlings

Can you keep them indoors? I’ve just potted mine up and the packet suggests keeping them at 15°C.

Also the north light is not the best as the seedings will become leggy looking for light.

They have probably stopped because the weather has become colder. I’d ease up on the water as too much in cold weather will rot them and the roots need to go ‘searching’ for water to grow.
You should Alonso pinch off the top of the leggy ones once they’ve got at least 4 leaves. They will then branch out.

There are four other pots and all have the leaves closed like the two in the pic.