I can't see the second set of photos well enough. Look with a magnifying glass and compare online photos of mealy bugs. Those could also be harmless spider webs.
Be very careful with temperatures on windowsills. Many people have plants freeze. Put a thermometer between plant and glass to get an idea.
I suggest LED lights. The initial higher cost is repaid in less than 2 years due to lower electricity use.
__________________ May the bridges I've burned light my way.