Jeremy we had our electrical sub add a few switched outlets on top of the beams in our great room - useful for Xmas decorations and for hanging lamps - and they are hidden if not used.
We placed wall sconces around the great room and tracks over our summer beam (I think that is what Chris called it) to up-light the roof area - the great room will take a lot of light to get it bright but not so much to add contrast - think about where your furniture will be placed and how you will use the room.
For your can lights - don't use them in insulated areas where they will "break" the insulation or air seal boundary unless absolutely necessary - if this is the case think about the detail of how you will air-seal and insulate (it is possible but know the plan before everything gets covered up and the spray foam guy is gone).
I would not be overly concerned about thermal bridge in areas with > 2" x 8" as the wood will provide reasonable r-value (zone 6+ you need to worry) - for any area above the ceiling do as you say - as the spray is applied to depth be sure to enclose the rafter/truss to 2" and no worry's at all about thermal bridge nor air leakage (also significant strength increase to structure).
On the sloped areas - checkout greenbuildingadvisor.com for some details on how to do this properly - use poly-iso with foil face and you have an air/vapor barrior or if in an area you need vaper perm use EPS/XPS but as stated earlier not that big of a concern in your climate for > 2" x 8" boards.
The areas I notice this the most is by pantry area that is 2" x 6" framed outside my TF - we have several corners and framing around window with 2 or 3 boards side by side and I can feel the cold and my buddies thermal imaging camera shows these very brightly. - if all my cabinets were not installed etc I would add layer of poly-iso in here (probably no more than 1") -
talk to your Spray contractor if you have any areas that need rigid board as he may be able to provide/install and spray around it - mine did this and worked well. In my case these areas were rim board to garage and needed backing to spray against
Also are you insulating the garage? or any rooms over garage? My spray guy put 2"+ out there in the ceiling then filled cavity with open-cell. My bonus room over garage is ~ 7000ft^3 (500ft^2 finished) that we heat/cool with a single 1T Mitsubishi mini-split (almost never runs) - key was spraying the entire barrier envelope and detailing all joints the spray could not cover.
On other item we did was have the electrical folks run a sub-panel to rear of house opposite my main panel - thought was for future hot tub, out door kitchen etc.
Ran 2 exterior switched circuits for Xmas lighting (can be used for other switched application also
Ceiling fan(s) for great room - make sure the box/mount is installed now and is sturdy as you may want a significant sized fan (I was looking at BigAss fans but found very nice units at Home Depot that fit TF style very well!) go ahead and wire for light kits, although I have not used them and not sure they are useful 18' up in the ceiling
. We put fan mounts in every bedroom even though we have not put fans in most rooms (easier to add now than later)
I notice you have several young people living with you - think about sound transmission - the large open room style of TF also allows NOISE to permeate :confused2: look for areas to add sound deadening material before enclosing - our house used all hard surface but we placed insulation in barrier walls between bedrooms and great room etc that helped - I found homosote before I finished the bonus room and placed this behind the sheetrock - works very well keeping sound contained
