Back to our regular scheduled program...
Rust is the probably the biggest concern. It will eat your budget alive and then some.
I like the idea of buying one half finished, or one that's finished but the buyer needs money ASAP.
Trim can be difficult but not impossible to find. If a lot of trim is missing, consider passing on the car.
You can peruse the various vendor websites (Centerline/Classic Alfa/Alfaholics/Highwood/Vick Auto/OKP/Alfa-Service, no offense intended if I missed someone) to see what parts are available and how much they cost.
The seats on a 69 will set you back like you wouldn't believe so either skip the 69 model year or make sure it has the correct seats.
Mechanical bits were shared by various models and it's not unusual to find a bigger motor transplanted. The 1750 motor is smooth as silk and pulls well.
The market is hot right now for what you want. It might cool, or it might go higher. Most of the cars don't sell at the top so be patient.
The BB has folks all over the place who can be another set of eyes and ears for you.