HELP! 3 Weeks Data in Italy - Newbie Questions!

[automatics]

Hi all,

Hope I can tap on your wisdom. Some context. I'm from Singapore.
I'll be travelling to Italy - for 3 weeks Entire country, from North to South, and back including some remote parts.

I'm looking at 1x Prepaid SIM for my iPhone & 1x Prepaid SIM for my dongle.
Is there a SIM can be used for both?
Or must I buy separately?

Some initial questions I hope you can assist with! Thanks!!

Understand I need a Codice Fiscale.
To apply online & printout, as per Effendi's guide.

1) Which provider can you recommened as the best coverage & data plan for my above needs?

2) Arriving in Milan - Is there anywhere I can pickup a card within the Airport? As I'm a very tightly controlled tour group.

3) I read Wind has the 1GB & 10GB plans that sound great.
Do they work as good as they sound? Do I find a Wind shop, buy & plug & play?

4) Is there anything else I should be aware of when using data in Italy? Any hidden pitfalls/traps?

5) I know the answer is probably NO. but is there anyway to get a card before arriving to Italy?

Grazie tanto! Grazie mille!