semar

the cables as shown on the railing will make a perfect ladder for kids to fall over the railing.
Ok for older folks who stay in their rocking chairs on the deck
Spending the money on a glass railing will make your insurance guy happy

the simplest way to determine window sizes is to draw an elevation and experiment with different windowsizes (papercut-outs). It does not take long to find out what you like.
Other things to consider: what effect will it have on the heating system. (heatloss - furnace too small)
are you loosing placing space - looking at a large cabinetback from the street or backsides from tv and audiosystems is not very attractive.
What will be involved when you increase the width of window - structural elements

Certainly the location of the beam is not in the best spot.
If the beam is in the center of the building width which appears to be ca 24' the better solution would have been to go with flat floor trusses for the whole span, eliminating the beam alltogether.
Since the framing is already in place I see the beam supported 3 inches bearing. Providing the PE has his header calculations right the hanger connection system is ok.(custom made hanger with top plate bearing). Definitely the beam should be raised to the underside of the topplates and the difference regarding windowheights adjusted on the bottom of the header.
I would also brace the bearing studs to prevent any buckling in the windowopening

my guess is they did not do this to save time or money.
I think they did not know that proper bracing was necessary. Poor training - we do it all the time like that - probably led to this. They most likely wonder why could this happen?
Expensive lesson learned.

To smalld
"custom home builder". Some actually get an award for framing walls plumb straight and square. Entitles them to call themselves Quality Builder, Top Quality Builder, Superior Construction, Best Builder in the Area, Award winning Builder, We are the Best
Sqeaky floors and stairs, sticking doors, CP trim (caulk 'n paint) - all no problem, just hang a 3000 $ chandelier in the 22' high foyer and install SS appliances in the kitchen and you can sell it as one of a kind custom home in desirable neighborhood

you would not want to wait to straighten the walls out when you have all the ceiling joists on. If the opposite wall was straight and plumb the correction would throw the opposite wall out of plumb.
So, straighten the walls first, then fasten the ceiling joists.
The turnbuckle method of course is the cat's miau, especially if you frame only with one helper

I would not feel comfortable with poly spray foam.
They talk about "lower" emmissions. How low can you go?
Just because it is approved does not make me feel safe.

Other chemicals were considered safe only to be totally banned at a later date.(asbestos, thalidomide, etc)

Just check the local news in Vancouver BC where a highrise building was repaired with polyurethene foam. Now a problem arose - cause yet undetermined - but all occupants had to leave their premises; for days now until an undetermined return in the future,

Foam? not for me

as we have experienced with cabinet fabrications, Europe is already ahead with prefabricated home construction.
Even foundationwalls can now be ordered made to measure.
Move - in dates can be as low as 3 weeks from completion of foundation subfloor.
In Vancouver BC some companies were up and running with this system until the Japanese market collapsed.
What will be next? Wal-Mart build your own?

a tiled cover for the drainpipes would be nice

I use either a horizontal metal hanging bar like they do in Europe or install a 1 x 4 with two inverted 45 degree edges and simply hang the cabinets on it.
When you install the first strip on the wall you can shim it if necessary; also when hanging it eliminates the temporary support (or helper) and the cabinets will always hang level.

As a footnote: I also use levelling legs instead of the 1x4 toekick. In the void under the cabinets you then can run additional electrical wires or plumbing lines if necessary without having to go into the drywall. The front is covered with a plinth