Acurite newbie question

Retiring in November. Ordered a 5 in 1 station so I would not get bored.
http://www.costco.com/AcuRite-Pro-5-in-1-Weather-Station-with-my-AcuRite-Remote-Monitoring.product.100291909.html

Thinking about also buying this 4 sensor weather display so I can monitor my sun room, garage, etc.
https://www.acurite.com/indoor-outdoor-multi-sensor-display-with-3-add-on-sensors-02076m.html

Confused by all the acurite options.

Can the 5 in 1 weather display display more than 2 temp/hum sensors?
Does the 5 in 1 weather display/sensors and the 4 temp/hum sensor display/sensors need to be on different channels?
Can one smarthub monitor all the sensors?
Does myacurite cost money or is it free for a certain amount of time?

Thanks
Tom