Transportation Questions

Hi all!
I will be heading to Japan for the first time mid-November and I have a few questions about transportation that I was hoping I could find answers to here:

1. I will be arriving at Narita at 7pm on a Saturday and staying at Asakusa for my first week in Tokyo. Doing some research, I think it is best to catch the Keisei Limited Express to Aoto Station, then change platform to get to Asakusa.
But from this webpage: http://www.japan-guide.com/e/e2027.html - the purple line seems to connect Narita to Asakusa - so is it possible not to change trains, or is Aoto some sort of end-terminal station?
2. I'm planning on buying the Tokyo Metro Open Ticket (2-day pass for 980yen from Narita Airport). Where in Narita do I buy this from, and does it activate immediately? Because, I'd like to use the Ticket on the 4th & 5th days of my time in Tokyo.
3. I'll be purchasing a Suica Card for Tokyo use, but also going to Chiba for a day. Does Suica work on the trains and monorails in Chiba?
4. I'd like to buy the Kodama Puratto Economy Plan ticket to get from Shibuya to Kyoto:
- Can I buy this from JR Tokai Tours/JTB Travel at ANY JR station?
- Do the Kodama trains only depart from Shinagawa and Tokyo Stations in Tokyo? (i.e. I have to buy train ticket from Shibuya to Shinagawa/Tokyo and then catch the Kodama to Kyoto from those stations)

Tokyo's train system just seems so complicated when reading about it online - Any help with these questions would be much appreciated!

Thank you!

I think it is best to catch the Keisei Limited Express to Aoto Station, then change platform to get to Asakusa.

The connecting train actually leaves from the opposite tracks of the same platform. In addition, there are a few direct trains.

But from this webpage: http://www.japan-guide.com/e/e2027.html - the purple line seems to connect Narita to Asakusa - so is it possible not to change trains, or is Aoto some sort of end-terminal station?

There are a few direct trains. But they are less frequent (every 40 instead of every 20 minutes) and slightly more expensive. Also, there are no direct trains from late afternoon:
http://www.hyperdia.com/

I'm planning on buying the Tokyo Metro Open Ticket (2-day pass for 980yen from Narita Airport). Where in Narita do I buy this from, and does it activate immediately?

The place of purchase is explained here:
http://www.tokyometro.jp/en/ticket/value/travel/index.html

It does not activate immediately. You have to pass through a Tokyo Metro ticket gate in order to activate it.

I'll be purchasing a Suica Card for Tokyo use, but also going to Chiba for a day. Does Suica work on the trains and monorails in Chiba?

Yes, it does.

I'd like to buy the Kodama Puratto Economy Plan ticket to get from Shibuya to Kyoto:
- Can I buy this from JR Tokai Tours/JTB Travel at ANY JR station?

No, only the ones that have a JR Tokai Tours office. In Tokyo, they can be found at Tokyo, Shinagawa and Shinjuku Stations:
http://www.jrtours.co.jp/shop/shutoken.html

JTB travel agencies, on the other hand, can be found scattered all over Tokyo, but if you lack Japanese language skills, I recommend to use JR Tokai Tours:
http://www.jtb.co.jp/shop/index.aspx

Do the Kodama trains only depart from Shinagawa and Tokyo Stations in Tokyo?

Yes, that is right:
http://www.japan-guide.com/e/e2018_tokaido.html

i.e. I have to buy train ticket from Shibuya to Shinagawa/Tokyo and then catch the Kodama to Kyoto from those stations

Yes, if you use a Puratto Kodama Plan, you would have to do that.

Thanks @uji! Much appreciated.