Yes, 10% humidity is very very low for this stage.

Humidty is very hard to control especially if you have really good air exchange.

I have not had this problem...perhaps some soaked towels placed in the room would help. Or a bowl of water....

If you are around them often, you can spray mist every few hours and the plants just LOVE IT

As for your rooting....fuckits hard to diagnose without pics....but...you can water her, then slowly lift her out of the pot and look for yourself at the rooting system.

Signs of needed transplanting are patches of heavy white...roots.....especially at the bottom and lower sides....where they appear to be growing onto each other in search of soil. If you have that, read the FAQ I have on transplant and have at it

How long are you veggin her?