A:AnswerYes to both quetions.this is not just a wifi. Yes you can use a micro sd card to expand your memory its one of the reasons i chosena samsung the 1st time!
A:AnswerIf you are referring to using your Note 3 as a hotspot... Yes, you can connect the tablet to the internet. I don't believe the proper drivers/software are in place for a USB tether.
A:AnswerThat's completely dependent upon your contract with your cell phone provider. You should check with them on how to set that up. Afterward your tablet as well as any other device can connect to it as you would any other wifi router.