I know that this question will take some time to answer but... .... Can..

Dialga- Spear Piller after you beat the 7th Gym
Heatran-After you beat the elite four go to stark mt. A guy named buck will be there take him to the magma stone go out and fly to s. Area See buck go back to stark mt. He'll be where the magma stone was.
Regigigas- after you beat the elite four go to the snowpoint temple with regice, regirock, and registeel.
Hedgey Mouse guy-??????????????????????????????????????????????????????????????

You're not helping us here...
What is the "yellow and black thing from the 2nd world"?
I'm guessing that "the one with the pink/red head" is Mesprit.
I'm also guessing that the "hedge mouse thingy" is Shaymin.

I take it that you already know Mesprit is in the wild grasses of Sinnoh? Good job.


Rotom: Go to the Old Chateau between 20:00 and 04:00 game time, and go to the room where you see a TV. Talk to the TV, and you'll battle the level 15 Rotom.

Giratina: Go to route 214, and go east along a new place called "Spring Path". In here, you'll find a cave called "Turnback Cave". This place is totally random, and as you'll read on the map, 'dimensions are distorted'. So every room you go in is a random room, so just go through random doors. If you go in the door you just came in from, you'll start back at the beginning. You'll eventually pass 3 pillars, and the next room is where the level 70 Giratina will be.

Cresselia: First, go to Canalave City and talk to Sailor Eldrich. Then, he'll take you to Fullmoon Island to obtain the Lunar Wing. While you do that, you'll have your first encounter with Cresselia. She flees, then pick up the Lunar Wing and return to Sailor Eldrich. Then, when he sails you back, Cresselia will be found in the wild grasses of Sinnoh, much like Mesprit. But save the master ball for her, she's much harder to catch.

Phione requires you to trade from Pokemon Ranger, and Manaphy requires you to breed Phione with Ditto, so you can forget about them.

Darkrai: You obviously cheated to get the Oak's Letter for Shaymin, so cheat to get the Membership Pass. Then, in Canalave City, go to the Harbor Inn and stay a night. Obtain the item and show it to Sailor Eldrich in-town. He'll take you to Newmoon Island, where the level 40 Darkrai resides.

Arceus: Like with Darkrai, cheat to get the Heaven's Pipe [or the Azura Flute, not sure what it's called anymore]. Then, go to Spear Pillar on the top of Mt. Coronet, and go to exactly where you originally battled Dialga. Use the flute there, ascend the stairs, and battle the level 80 Arceus.

If you already have 2 of the pkmn that live at the lakes then you probally can't catch Diagla anymore. You get him when you battle Team Galatic at Mt. Cornet and you battle is after beating Cyrus at the peak of Mt. Cornet/Spear Piller.

Heatran is at the back of Stark Mountain. To get there you need to have the National Dex, because Kanto Pokemon are there. When you first go inside of Stark Mountain a pkmn trainer Buck will ask to join you. You go to the very back of the mountian to a cave. Buck will blabber some more then go in and take a rock, then leave. Use an escape rope and go back to the survival area and go to Buck's house west of the pkmn center and talk to the people in the house. Buck will leave after you talk to him. Go back to Stark Mountain and inside the cave where the rock will be Heatran at Level 70.

Regigigas is in SnowPoint at the Snowpoint temple. To battle him you have to have the 3 Regi's from emerald/ruby/sapphire in your party. Navigate you way through and at the bottom of the temple is Regigigas at Level 70.

The Hedge Mouse better know as Shaymin is only avaible*sp* at a Nintendo Event of through Mystery Gift.

Wait a second, next time, word this differently.
Separate the Pokemon you already caught from the ones you want to catch.

I took all the Pokemon you listed as ones you've already caught because you didn't separate it.


Dialga: Too late to catch him now, since you've already caught 2/3 Lake Pokemon.

Heatran: When you've obtained the national dex and beaten the E4, he's eventually found in Stark Moutain. You'll help this guy named Buck get to the end, and then he'll leave with the treasure. Go back to the Survival Area and in the house west of the Pokemon center. Talk to Buck, and go back to that room in Stark Mountain. A level 70 Heatran will be there.

Regigigas: Transfer the 3 Regis from Ru/Sa/Emerald, and with them in your party, go deep in Snowpoint Temple [obviously, when you've obtained the national dex]. Deep in there will be the level 70 Regigigas.

The hedge mouse thingy, or better known as Shaymin: By cheating/going to a Nintendo Event, obtain the "Oak's Letter" and go to the end of route 224. If you've been there before, but by judging from your question you haven't, there was a polished white rock at the end of it. Instead, there will be a route that extends beyond that rock that leads to a flowered field, and level 30 Shaymin in it.