It sounds like you need to bleed the system of air.
Which brakes are you replacing front or rear or all four It shouldn't cost more than $100 with out parts and labor Or you can do them your self it's not that hard at all unless your are doing the rear brakes which will require a special brake spring tool
If you want the parking brake to work, yes.
1996 mercury sable. If you haven't any experience with doing disc brake work I would recommend purchasing a shop manual for that vehicle to help you do this job correctly and safely. Good safe brakes are a number one priority!
No, doing a brake job does nothing to the front end.
Air in the brake system- Brake system needs to be bleed and fluid needs to be added while you are doing that.
A mechanic would be able to help you with doing this. It is best to do it this way to avoid any problems later on.
And why in the world would you want to do that, as the rear brakes which are operated by the parking brake are already activated by the brake pedal. Do not even think of doing this.
anti lock brakes ( ABS) will automatically work when ether the brake is applied heavily or the wheel looses traction on the road surfaces when braking you will feel the brake peddle "bounce" rapidly this dose not work on most cars doing under 30mph as the vehicle is not doing a sufficent speed for it to be affected Stomp the brake and steer around the obstruction. Do not release the brake pedal and do not pump the brakes. The Anti-Lock brake system will do this for you.
NO, If your brakes were serviced correctly then they will not be out of line. Have your brake system inspected by a professional. If something is wrong, doing what you describe may cause you to loose control of the vehicle if the brakes lock up.
You Probably have air in your brake lines Or you may have low brake fluid. Mechanics can bleed the brake lines which will remove the air out of the lines. I do not recommend doing this yourself.
You can take your vehicle to Les Swab and they sometimes will give you a free brake inspection before doing any actual work to your brakes and charging you.
Your handbrake will be adjusted when you have your rear brakes adjusted by a mechanic. You can go to any brake shop and have them clean and adjust your brakes and this will fix the handbrake by doing so.