Since my planner is not an engineer, I'm looking for a roof engineer/architect who can calculate the load of the roof/truss and tell whether "Drag" truss is required?

Definitely hire an architect for this.

Between hiring an architect, splitting electric, adding a furnace, SAC & PDF fees, building permits, and fire/sound requirements the costs add up quickly.

I haven't done anything to the roof itself but add a beam that my architect said I should add even thought it's not in the plans, but this construction person said I didn't added correctly.

So I got w/ my architect friend and he found a solution, which I presented to the builder.

So right now set up is 4 apts each floor but what size.. 2br's..I'd see what potential is for 1 brs' and studio..Get a general contractor, a designer, architect to do a floor plan best unit design, have to be top notch to be aware of building codes and state codes for apartments. so floor plans meet size requirements.Could be what's decided is to also gut 1st and 2nd floor to accommodate the new.You'll of course need a plumber (HVAC), electrician who would be part of General contractors crew.Once the architect has a design you'd get bids from more than 1 contractor.I'm working in a 100 year old building the owner is working with a developer,, it's going from office to apartments they've decided best and highest use is 1 BR and Studios, and everything inside is going to be a gut.. even moving elevator shafts. 

If you want to become a doctor, attorney, architect, etc go to colleges. 

what kind of structure recommended for better pricing(wood/masonry/metal), any recommendation for Architects/Engineer for the planning for getting township approvals.

Unsure if I need an actual architect or if I can just buy a plan already done online. 

You may need to hire an architect or other planning type to research what local zoning regulations you will need a variance approval for.