Chocobo Racing: 2 questions

I started racing a couple weeks ago and about to breed a 3rd generation choco, aka my second time breeding, but there were 2 things I need to know that a guide either didn't explain clearly or was outright wrong.

1. How do you increase stars for stats without lowering others? For my first breeding I bought G-9 permissions until I got one that had 4 star speed, 4 star acceleration, 3 star endurance, 4 star stamina, and 1 star cunning, and of course my choco had 2 stars in each. After breeding my stats were the same as the permission except cunning which stayed a 2 star. Now for my 2nd breeding I want to increase endurance and cunning without lowering the 4 star ones. If I get a permission with 4 stars in cunning and endurance but lower in the other stats will the 4 star other stats be lowered?

2. How do you carry over a skill as hereditary skill? A guide told me you can choose which to keep and recommended keeping a specific skill for your first breeding, so I taught my choco the skill and chose to keep it when I retired her, but after breeding the new choco's hereditary skill was that of the permission choco's instead of the skill from my choco. Permission one was a cruddy choco steal II, so either the guide was wrong, or didn't explain it clearly, or SE changed it to make hereditary skill random chance from the parents' skills.

So now at my 2nd breeding I want the skill I choose to pass down and want to improve the lower stats without lowering my three 4 star stats.

RNGesus and a LOT of incest breeding lol

1, As I understand it, and I may be wrong, each stat is inherited from one parent or the other. They are not averaged.

2, Hereditary abilities are inherited from one parent or the other. 50 - 50 chance.

It's been a good while since I've done any chocobo breeding, but if I remember correctly, it uses the ratings of the grandparents to determine the rating of your chick. So if you want four stars in a certain stat, all of the grandparents have to have four stars in that stat to guarantee it being passed on. This is why you usually end up breeding multiple birds at a given pedigree level and crossing them with each other to lock in star ratings. It's a slow process unless RNGesus really likes you.

The hereditary ability the chick gets can come from either parent, so it's 50/50 you get the one you want.

They're also no reason to buy a P9 permission if you're breeding a P2 bird. Higher pedigree permissions do not guarantee better stats. It's all luck of the draw.

There is a lot of RNG in chocobo breeding.

The first priority, get your stars in order.
To increase the stars - purchase P9 breeding. These have the highest stars available. You will need to buy a bunch of them and be ready to throw several away. Basically, you are using GIL to offset the RNG of the star disbursement.
You cannot buy a 20/20 breeding I think it maxes out at 14 or there abouts. But as 14 you will have usually 2 or 3 4* stats and a couple 2* star stats.

Once you get a decent bird star wise all stats 3 or 4 stars, you need to start breed that bird with its offspring. This will lessen the star RNG by having two parent birds with good pedigree stars.
During a couple of mid pedigree cycles you might need to return to the GS P9 breeding to fillin the gaps your 4* pedigree.

After the stars are taken care of you just need 1 or 2 more breeding cycles to set up your inherited skill and fair/foul weather traits.

My birds for example, have had terrible RNG, so I have been stuck at about a 17/20 star bird for many breeding cycles. I am considering starting over.