I mean it could work if you are willing to give up the waveclear provided by minion dematerializer. Personally I wouldn't go for it though.

BTW, how can I put doran's ring with the image and all informations?

Doran's Ring vs dark seal
dark seal gives more mana, almost same ap, more heal from corruption, and you can totally snowball. Dorans ring just gives you 60 hp + 15 ap, (the mana passive is unique), so dark seal give more sustain, more snowball potencial and a litlle less AP(7 vs 15 AP).
And this is what lol wiki says:
If you use your three Health Potion item potions, you're getting 112.5 health from this item's passive effect. This is 52.5 health more than Doran's Ring item Doran's Ring and increases its value to Gold 766.25, making it 218.93% gold efficient.
If using a Refillable Potion item Refillable Potion instead, it provides 62.5 health, making the item worth 586.25 - a gold efficiency of 167.5% - increasing by Gold 228.75 with each back.
As you can see, this is a lot more efficient then double doran's ring.

No, it does not. If you read the description it'll tell you that it does true damage based off of level and has no scaling off of any AP or AD one might have.

Hello!
I tried multiple choices including electro in the past and no - it's totally not worth it. And when I am looking into your build and knowing how the champion works, I don't see it being better than current build. In plat elo you might've found success with it, but fact is that with this build I am cappable of stomping plat games. But obviously if the build fits you, it's all fine and keep it up!

Morellonomicon might look like good idea, but you just delay your powerspikes with it. Obviously, AP Kogmaw consumes a lot of mana, but if you know how to manage it, you dont need Morello for additional mana sustain. In addition, cooldown reduction is not that insanely important. If you had more item slots, it would be great, but currently its not worth to drop anything out of my build - or if you want, you can tell me what would you omit and put there Morello instead?

For Quints - as I mentioned, it is for your ult ranks... it is crucial to hit level 16 as soon as possible (or possibly level 11 as well). You can use magic penetration quints if you feel confident that you can get your ult ranks without it, but it is just quality-of-life thing. Once you hit level 16, you pretty much become artillery beast, which allows you to tear down towers with ease. About AP quints - you dont want these, since AP Kogmaw doesn't really have too great AP ratios, so if something, go for magic pen.