Congrats on getting some tarantulas! You made some great choices
You're right, there are tons on inconsistencies! It is sometimes quite hard figuring out what is best to do with all that info!
Fire legs don't require much humidity as adults but as slings do. Around 70-75% is fine until it reaches 1 1/2-2" then it can handle 50-60%.
I have a small avic sp. sling that has been doing very well. Personally, I don't mist any of my T enclosures to raise the humidity, my T's really don't like it! What I do to keep the ambient humidity levels up is to moisten the substrate regularly. Not so it's wet but damp. I also moisten one side of the enclosure to try and give a humidity gradient on the ground so the T finds a comfy space that it likes.
The setup you described for your pink toe sounds just fine as well as the temps
Good luck and keep us posted. If you can, post pics of your new critters when you get them
And always feel free to ask questions! It's the best way to learn
Pixie