Tickington for skill seeds as 2 mimics re-spawn each time you leave Tickingtom. One is on that ice dungeon on DQIV where you get a fever medicine in that game and on that other dungeon where you fight a corrupted Pegasus. For the other seeds you need to check the bestiary.

Not a fan of the 2D content. And considering you only need 73 skill seeds, you'll probably get 40+ on one playthrough up to chapter 3. Which means you'll have all you need with one dupe anyway. Though, it's fair to say they are unfairly done dirty if you don't have enough by chapter 3, as the only non-dupe non-2D way is to farm them by rain.

I know Attack seeds is bottom left island, for both chapter 1 and 3 (didn't check for 2), though they are not worth it because of super seeds.

Will check the rest eventually.