Sorry to hear that she's still plucking, but it sounds like you are doing everything right. With all the effort you are putting in she will be much better off even if the old habit of plucking takes a while to go away.

Do you know when she plucks? Do you ever see her doing it?

As far as getting her to use the toys I do not know of many ideas, except for foraging toys: be sure to start simple and be sure she sees you put the food in them. The extreme simple end would be to put a good food item next to her and let her take it. Do this a couple times then place the food item there with a small piece of placed over it, perhaps the coffee filter, but do not cover it completely. Next, cover it completely but don't wrap it; then wrap it gently/loosely in the filter, etc.

Also it is best to limit her regular food a bit. This is easiest if you feed her her normal food at specific times of the day. Perhaps if you watch for when she eats regularly - does she eat at a particular time of the day - if so take her food away an hour or two before that regular time, then when her regular eating time comes start giving her the foraging options.

Getting a parrot to forage for food is making them work for food - working (a little bit) for their food is healthy, but if there is a constant supply of free food there then she will not work for it.