I have a bike frame that I want to finish by the spring

Older bianchi steel frame, but it looks good and I caught a great deal.

I am looking to upgrad the components then replace the frame down the line. I have a medium budget and some specifics but other than that I'm looking for some good insight.

Singlespeed/front disk brake/ maybe a bag(10mi commute). road inspired, commute ready, singlespeed... haha they are some high hopes but we'll see.

heres a list of products im looking for;
(dark fork with disk brake compatability, Single front wheel with disk, single speed crankset, single speed rear wheel, budget race saddle, etc.) yadayada as you know the list is long.

but im ready to build and want to find some parts that will convert to higher end frame nicely.

Do i need a special lever for disk use?