OK, this makes more sense.

The bleeding...if you blocked the pedal half way down you should not need to bleed all four. If you got lucky (and it sounds like you did) you do not need to bleed all four. If you want to prolong the life of those rear calipers, flushing all the old fluid out of that circuit is a wise idea unless you have done it in the last 30K miles or 5 years.

Pry all the pads back a bit with car pointing a way you can drive without using them (leave the car in neutral, pry them apart, start it and shift into drive). Accelerate to at least 30 mph and SLAM on the brakes but do not come to a full stop. Do this at least 3 times but preferably 5 or more and the closer to 50 mph you can get, the better. Drive softly for about 10 more minutes and then park it without holding the brake pedal down.

IF your problem is pad glazing this has a small chance of solving it. At the very least it will make it better. It will bed the pads a little better.

The brand and spec of pad might help but there are three variables I can think of:

If the pads sound like they are grinding in the rear, they are not retracting enough to not drag. This might improve as soon as the new pads bed into the old rotors (just guessing). This might be a function of rusty ways as mentioned earlier.

Ditto if it is the front making the noise.

Finally, it might just be the compound or the lack of anti-squeal pads on the back of the brake pads.