Personally I actually do think the kratom would help. Obviously if you're coming off of 600 mg + per day the kratom won't put much of a dent in it at all, but part of the wd's from lyrica are being demotivated and for lack of better words "depressed", like it's tough for you to even get out of bed and face life - kratom will help in this regard.
I also think the phenibut will put a dent in your lyrica wd's, but again it depends on how much you are coming off of. You will still "feel" the wd's, but phenibut will help ease some of your anxiety and depression. Especially if you don't have a tolerance to phenibut, take like 3+ grams and I don't see how it wouldn't make you feel better.
IMO just because something doesn't effect the same brain functions doesn't mean it won't make you feel better. I think some of the advice here is speaking in terms of a purely scientific sense and doesn't necessarily apply in terms of how kratom and phenibut would contribute to your overall sense of well being. For example, benzos will make you feel a hell of a lot better when going through opiate wd's even though they don't effect the same brain functions.
Also, there was a point where I was averaging over 600 mg per day of lyrica for over 3 months and switching to gabapentin worked beautifully for getting off it. I didn't even taper off the lyrica, just went straight from my 600 mg / day habit to something like 2400 mg gabapentin and suffered zero discomfort whatsoever. Then from there it was actually really easy to drop my gabapentin dose to 1800 mg after one month then to 1200 the next month. I took 1200 mg of gabapentin for one month then got off that cold turkey and the wds were VERY minimal - basically a bit of insomnia for about a week, but that's it.
So, if I were you, I would do whatever it takes to get your hands on some gabapentin, especially considering how extremely easy it is to get a doc to write a script for it. You could have used the money you spent on kratom and phenibut towards getting some gabapentin and gotten way more bang for your buck in terms of avoiding wd's.