The same filming location was used in both movies.

Just Lou had visited the site a few years back and posted some pretty good pix of "the compound" (actually two houses with a fake wall built for the movies).

The novel backs you up, Whisper. I believe it says that Michael contrasted his calm with Enzo's shaking hands. It wasn't macho posturing on Michael's part--it was his growing self-realization that he needed to stand by his family at their time of need. It also subtly reinforced Michael's "icy calm" nature in the face of danger and other stresses that would cloud other people's minds with emotion and harm their judgment.

I questioned this a couple of years ago. I referred to the pink house across the street in GFII. As others have stated, for GFII, they apparently removed or did not reconstruct the fake wall that was present in GFI. That's why you can see that pinklooking house behind Frankie et al.

Mike also smiles in a deleted scene in II where Franseca (Sonny's girl) asks his permission to marry Gardner Shaw. The scene paralleled Connie's request and Mike's reaction to that so well that I wish it would have been included in Part II.

From which mistress did Vincent Corleone come? . . . The broad upstairs during Connie's wedding, or the dame in the upstairs apartment?

What "dame in the upstairs apartment"? If you mean the one Sonny visited (and then walked downstairs with his bodyguards), then its the same one he boffed at the wedding (Lucy Mancini, Connie's maid of honor).

They're the same person.

What are the names of the members of the family by "rank?" . . . and what are their jobs/functions?

Obviously "Godfather" is at the top and controls the entire family. Where does it go from there?

Godfather

Caporegieme or Capo's (Captains)

Then I think Buttomen? Someone else will have to go from here.

What is a consigliere, and where does he fit in?

The consigliere is the top advisor to the Don. He is probably the one person in whom the Don reposits his trust.

See the scene at the wedding when Michael and Kay are eating their lasagna.

MICHAEL: "Not a Sicilian, but -- I think he's gonna be consiglieri."

KAY: "What's that?"

MICHAEL: "That's um, like a counselor -- an advisor -- very important to the family."

The consiglieri is the only one that takes orders directly from The Don, which is why the position is so important. And that's why it was strange Vito would have a non-sicilian as his consiglieri. Sicilians have a strong belief in "omerta", the code of silence. Where as Hagen was an adopted kraut, mick.

Yes, that was true in the Corleone Family. Puzo made a point of Vito's carefulness in giving orders only to one person at a time--Hagen, his consigliere--to prevent having witnesses to his criminal orders in case someone turned rat. He also gave orders to Luca directly, without Hagen, but never to more than one person at a time.
Real-life Dons don't necessarily follow that pattern. The consigliere may be a respected Family elder, who's retired from active racketeering and is functioning as an adviser to the Don. Or the consigliere may be one of the caporegimes, who has people under him and rackets to look after in addition to his adviser role. Sometimes the roles are interchangeable: one of the Federal surveillance tapes caught John Gotti telling Sammy Da Bull: "What would you like to be--underboss, consigliere...whatevever makes you feel better."
Modern Dons are seldom as careful as Vito in passing on orders without witnesses. That's one of the main reasons so many of them have been ratted out, and have ratted out others in return.

Gotti wasn't careful?

And the funny thing is that he used to call Angelo Ruggerio "Quack Quack!"

How does the saying go?

The pot calling the kettle a loud mouth.

Don/Godfather - Head of the Family
Consigliere - Advisor to the don
Underboss - Next in line to become head of the family
Capo - Captains of the mob and take care of the day to day activities.
Made members - People that are recognised as being part of the mob.
Associates and ousiders - People not in the inner circles of the Mob see Goodfellas

I hope that helps.