I suspect that any reduction in temperature, below perhaps 20 degrees C, will probably slow things down a bit. If temperatures fall below 10 degrees C (or thereabouts) then I doubt that they will grow at all, it doesn't seem to do them any harm although they can take a few days to get warmed up and growing again. As a general rule I think they can be treated as having a similar cold sensitivity to tomatoes. If they are treated like this then I think they will do well, although I think that they are actually much more tolerant of the cold than tomatoes are (but if they are too slow getting going it will be winter again). I think that the flowers are probably a bit more picky about the conditions.
I think it's easy to fret about seedlings, when what they really need is to be left alone to get on with it. Remember that until they have about three sets of true leaves they don't really have enough leaf area to do any serious growing.
In the meantime I would strongly recommend a sundance
:dance2: