Pulsating and screeching after changing disc brake pads
Unfortunately you have done nearly everything possible. Some brakes/forks/frame/pads/disc combination just do not work nicely. 

The one remaining thing you have to change is the disk. As the pads bed in, they lay down a thin layer of pad material on the disk, it is the microscopically thin layer that allows the braking to occur. If the bedding in is done poorly, the layer is uneven, and further bedding in may not even it up. Changing pads means the material laid down on the discs may not bed in with the new pad material. Sanding the pads disrupts (I won't say removes) this microscopic layer, allowing a new layer to be laid down when bedding in again. If the new layer is laid down evenly, the brakes will not squeal. 

A final option that may (or may not) work it to change the disk itself. The obvious choice is a different type, but even this is no guarantee of quite brakes.  

You really have three choices - go back to you old pads (They may now squeal), tackle the disk (sand or replace) or live with it. 

Use a fine (400 or even 1000 grit) wet and dry sanding paper. This can be done with the disk in place, but is easier if you remove it.  There is no guarantee this will work, new discs are sometimes the only thing you can do.