KIREEK I totally agree SA1 is better as a game than SA2 but as a chao fan more than a sonic fan I had to get it just for the new chaos value and the new gardens rock to!
Anyway, I'll help to clarify on your problem:
"Sonic Chao-
Start with a NORMAL chao in the STATION SQUARE garden.
Give that chao 20 pink animals."
^ Start with a normal chao as stated, and feed it run-type animals only. Keep feeding them to it constantly until it evolves. After this it should somewhat resemble the picture of dash I posted a while back, but not gold obviously. Keep feeding the chao run animals and gradually the spikes will become larger and you will have a sonic chao.
The chao must have a neutral alignment, but then, I think they all do in SA1.
"Tails Chao-
Start with an ORANGE chao in the STATION SQUARE garden.
Give that chao 20 pink animals."
^ Lies, all lies! If you have a GBA and a link cable and PSO 1&2 on gamecube play the fake in yellow quest. When you return to P2, straight away pipe back down to the last room and walk around the waterfall. A chao pops out and gives you a mini game to play. It's tiny chao garden from sonic advance. The chao you get in that mini-game IS the tails chao. You cannot breed a tails chao and I'm pretty sure they're immortal!
"Knuckles Chao-
Start with a RED chao in the STATION SQUARE garden.
Give that chao 20 pink animals."
^ Lies, knux chao are from a japanese convention of some kind only.
"Amy Chao-
Start with a PINK chao in the STATION SQUARE garden.
Give that chao 20 pink animals."
^ Lies again. Same as knux chao.
"Big Chao-
Start with a PURPLE chao in the STATION SQUARE garden.
Give that chao 20 pink animals."
^ Lies for sure, and complete lies at that. There is no such chao.
"E-102 Chao-
Start with a BLACK chao in the STATION SQUARE garden.
Give that chao 20 pink animals."
^ Even greater lies than those just above.
"Chaos 1 Chao-
Have a light speed chao. "
^ Lies.
"Zero Chao-
Start with a GRAY chao in the STATION SQUARE garden.
Give that chao 20 pink animals."
^ What the hell is a zero? If by zero it means chao zero, it's lies. Look to the chaos chao guide you posted for the real deal.
"Dr. Robotnik(aka Eggman) Chao-Start with a NORMAL chao in the STATION
SQUARE garden. Give that chao an animal to have a jewel on its head."
^ Definate lies.
"Chaos Chao
To get a Chao that looks like Chaos you need to get a regular Chao, and make it
rencarnate 3 times. Then after that happens, you must give that Chao every
animal in the game, then the Chao should start to evolve. To make sure the code
worked sparks of light should start popping out of the Evolution Egg (the egg chaos
go into when they mature). NOTE: You cannot alter a Chaos Chaos' apperence no
matter how many animals you give it."
Somewhat accurate (will make a normal chaos chao/light chao) but still mostly lies if you're looking for a chaos zero chao. Also you need reborn only twice. The one of every animal part IS accurate. Feed it one less or one more than it needs and your chao will fail to evolve correctly!
Breed a Shiny Purple Chao with a Jewel Chao of any kind to get a semi-invisible chao that has a Chaos Zero colored texture. Then make this chao into a neutral Chaos Chao (Light Chao) and you have a chao that looks just like chaos zero.
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Characters you left out

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The NiGHT chao can be made by feeding a regular chao fly cores or animals. The chao must have a neutral alignment!
The Omochao/Robochao from the chao races and SA2 can be obtained by attending certain conventions in japan and like the other otherwise un-obtainable character chao is thought to be immortal. The tails chao is immortal but can be obtained from PSO as well as conventions.
Shadow chao:
Start with a normal chao and feed him only run cores/animals. Make him of the dark alignment.
Super sonic chao:
Same as sonic chao but use a shiny yellow (not a gold) egg.
Hyper shadow chao:
Same as shadow chao but use a white-red two tone chao - I think. I could be wrong on this one. I haven't found it on a site or made it myself it's jsut a theorey. I guess a shiny white chao of some kind could possibly work to!