Tokyo Subway Ticket or Suica

I'm not sure wheter I buy a Suica Card or the Tokyo Subway 3 day pass.

I already have the JR Pass.

Is that Questions:

1) The Tokyo Subway Ticket (3 day pass) is available for all Tokyo metro lines (except JR)?

1) if we need to use on the same journey (to go to a place) Tokyo Metro, Toei Line and JR line, is it possible to use the Tokyo Subway Ticket (day pass)- for Tokyo MEtro and Toei Line - and the JR Pass, so that we don't have to pay anything else on the trip?

2) Using the Tokyo Metro Day Pass is necessary to change for a ticket on the subway stations?

3) To use Suica Card isn't necessary to exchange for tickets to use on the subway stations?

Thank you,
Elaine

Dont know which pass/card is better depends on yr plan.
Basically Suica/PASMO(as IC) are not discount pass
just no need purchasing tickets process and for shopping as e-money instead cash.
http://www.jreast.co.jp/e/pass/suica.html

1)
Pass not valid for JR for Toei and Metro all lines only.
http://www.tokyometro.jp/en/subwaymap/
JR(all 6 groups) hasn't subway(underground) lines.

2)
Just insert ticket gate.
http://www.tokyometro.jp/en/tips/metro/index.html
https://youtu.be/DlAaNqSXfXM

3)
Just touching.
http://upload.wikimedia.org/wikipedia/commons/b/bb/Iccard.gif