gfa is gross floor area. it give u an indication base on project completed in the past. so u can figure it out the price. usually developer estimate cost backward. NFA stand for what?

plywood then hardwood support below. u mean this hardwood right? hardwood is because this wood can stand the load and won't break even it bent a lot due to heavy loan. concrete grade nothing to do. there are certain spacing to be comply. anyway nowadays is system formwork era. most architect insist to use system formwork.

shear wall is generally deeper when u cast the concrete. it's poor vibration especially bottom part where concrete can't reach perfectly. also rebar congestion make it difficult to vibrate the bottom of shear wall. rectification is depend the severity of the hollow / honeycomb it have. hack the hollow part then put the formwork and pour non-shrink grout is the general solution. but consulting engineer will tell u if they want other solution if the case is serious. they might want u to hack entire shear wall and redo.

gbi got score index. depend how many point u wanna achieve. and how u get those point from