The carburetor is a Holley 2280 (a 6280 is the computer controlled version of same carburetor, which you don’t have), which is a decent unit. I prefer the Carter BBD – but this one will work – with one possible exception.
I don’t see the port going to the vacuum advance, which you will need.
You do not appear to have all of the parts for the EGR to work correctly. In this case I might recommend removing most of the EGR components (or leave them in place but disconnected).
Note: if this car was built to Canadian specs, then EGR system might be correct. It is not, for US cars, though.
Pic 16
Orange circle goes to the charcoal canister – It can be left open if you like but I personally think you will get slightly better mileage with charcoal canister operational (less fuel vapor loss).
Blue circles. One goes to brake booster and other to PCV valve. The PCV hose is an odd size (11/32” or 8.73mm). A 3/8” hose is too big and 5/16” is too small. A 3/8” with a small hose clamp(s) will work – but looks tacky.
I think there is a port marked with red circle – but can’t tell for sure. That port location is the one going to disturber – on the Carter BBD.
Most 2280 carburetors did not use vacuum advance – so it is possible you do not have that port.
Gray circle is hose going to the Lean Burn computer (ESC) and can be plugged.
Pic 17
Blue circle is the Coolant Switch. It turns off the EGR Valve operation when engine is cold.
Black X – EGR Valve
I suspect the carburetor port for other end of EGR hose is located at white circle – but might be mistaken.
The red circle is throttle return spring and spring bracket. There is a bracket in that area for throttle return spring to attach to. Also, it does not appear to have the correct throttle return spring on it. This might not matter – but I am picky about those things. After driving cars that throttle will not close – causes underwear to get lumpy real quick (if not accidents and/or death).
Pic 18
Red circle is port to air cleaner temp switch/hot air door in snorkel.
Blue circle is intake air temperature sensor. This part can be removed and pope plug installed if not using Lean Burn (ESC) – if wanted.
Pic 21
Left side exhaust pre-cat with transmission cooler lines right on top of it.
Pic 22
Right side exhaust pre-cat. I would recommend having a new exhaust Y pipe made and toss both pre-cats to the curb. It will make engine reinstallation SO MUCH easier, as well as a reduction of under hood heat and reduced exhaust backpressure.
A vacuum diagram for '86 Canadian M-body - which might help you.