All it has is 2 extra cameras, so I'd say no.
They are basically the same, except that the Touch will fit in your pocket, while the iPad won't. So if you value the portability that comes with a Touch, then it may be worthwhile.
It depends on what you are planning to do with the ipad.
No
YES
Depending on what you are planning to use the iPad for, then yes it can be worth it. However, if you just want the iPad to "have it" then it may not be worth it. If you are on the go and need quick access and like to use your laptop wherever you go, then yes it is worth it.
Yes, after buying Numbers from the App Store on iPad or on iTunes for $9.99
It really depends on the accessory. If it's a screen protector for when it's not being used, then yes, it is worth buying. If the screen gets messed up then it makes it hard for the tablet to recognize the touch.
It is worth US$499.99
A 3rd generation iPad is worth about $90 today in 2020.
Do $500.00 worth of work for her.
$200 if first generation, $300 if second (iPad 2).