hi florin91, I think the first link you provided is a must to be able to gain root access on obscure hardware and I hope to be able to utilize the contents on that second one at some point too. thanks.
here are some alternatives app stores if you do not have or do not want google gapps for whatever reason.
I have not used them but they were preloaded on my device as it was sold new in the box.
and these next links I have used. they are where you will find apps that can be directly downloaded from another machine and then "side loaded" into Android and installed directly. in no particular order and they are of basically unknown origin so use common sense and be careful.
I would like to find a download alternative similar to these except one that also provides the checksums with each .apk (if that is possible?)