A question on editing exsisting Pokemon VS hacking Pokemon from scratch in Heartgold with Pokegen

This is my first post here and I made this topic specifically for this purpose. Anyway, what's up?

I am using a NDS Backup Adaptor with PokeGen and a retail copy of Pokemon HeartGold.

I recently logged in 999 hours on my Omega Ruby game after getting all the Maison Tropies and re-breeding most of my legit entire living dex to be near perfect. I figured, what the hell, I should go back and play Heartgold and Black 2 and do the same thing.

So, many battles and gym challenges later in the mystical land of Johto, with my trusty 3 31IV Meganium and Drapion I bred, I figured I'd do the same for most of my Pokemon in the older games and fully complete the Battle Facilites this time. I beat the game at 85 hours, I'm now at 103 hours, 213 eggs later and only 4 competive level Pokemon to show for it including the first two. I tried RNG for 4 days, failed at it and dabbled in Pokesav and came across PokeGen.

I had no way aside from RNG to get a 6 IV Ditto so I created one in Platinum. Being parinoid about cheating and having this thing turn into a bad egg, I sent a copy of it all the way to Gen 6. I figured if it passed Bank's hack check, could be used online, and Wonder Traded away, it most likely would be ok. 3 days later in each of those files and all my data is great.

Now, I don't intend to hack to send these to Gen 6, like I said, I already have most of what I need there bred legitimately, I just want to have competitive Pokemon in Gens 4 and 5 for the ingame. Without spending 20 hours and not getting anywhere NEAR the results I'd get in ORAS doing the same thing.

Just hacking them in with PokeGen doesn't sit right with me, so I figured if I was going to do this, I may as well breed for the egg moves I want or catch it in the wild, and then use PokeGen to edit the IVs of the Pokemon already in the game. But is this safer for my data then just editing a new one in from nothing?

I tested this on a Growlithe I bred that had 31 in Attack/Def/Sp Attack and crap in everything else. In the Main tab I used the PID Finder to find a 31/31/31/18/31/30 Growlithe. Everything else was the same as when the game created it so I saw no need to fiddle with that. I loaded it into my game and so far it SEEMS fine, but IS it fine?

I backed up the save and I see the Trash bytes in the default name, like I hear legit Pokemon have, but I never set it, it did it by itself. I nicknamed him in the game and saved. Is it good to modify Pokemon using existing ones as a base or should I be doing it from nothing?

I suppose the long and short of it is, since the data is being modified from a Pokemon caught in the game already, is changing the PID of it to match the modifications going to make it a Bad Egg or anything of the sort down the line? Are there any other steps I need to take to ensure the Pokemon is a ok or is that well enough?

Can the same PID be used by another Pokemon ever?

Does Pokegen produce illegal PID combinations when you ask it to generate a PID?

I spent a few hours EV training some bred Pokemon I enhanced the IVs from and they seem just fine a day later. No Bad Eggs in other games either.

Bad eggs only occur when the checksum is invalid, if you're using pokegen this should never happen.

Well, that's a relief. So essentially, as long as I make sure the PID is correct with the edited IVs from Pokemon caught in the game I should be good.

Thank you.

The PID/IV coorelation really isn't important, even tournaments during the 4th gen didn't check for it. It's just a side effect of generating IV's right after the PID in a chain.