If that temp is accurate then probably no permanent damage will result. It may slow growth for a bit is all as most all you list are tolerant of temps in that range. But do keep in mind that "reported" air temps and actual temps at the level of the plants that would show on a thermometer placed there can be quite different.

Dave

"Heat-loving flowers" covers a lot of territory. There are tropical plants for instance that begin to show damage at 55F and may be severely set back or even killed at 45F (seedlings would be even more susceptible).

If we're talking about commonly grown annuals, they should come through fine.