Is there any way to chain-breed toxic onto these pokemon in genIV without smeargle?
Okay then.
1). Chimchar/Monferno/Infernape learns Toxic as a TM. 2). Squirtle/Warturtle/Blastiose learns Toxic as a TM. 3). Charmander/Charmelon/Charizard learns Toxic as a TM.
I also know you mean to teach a baby Chimchar/Charmander/Squirtle it as an egg move. In that case:
1). Breed a Male Roselia with Toxic to a female Ponyta/Rapidash until you get a male baby Ponyta/Rapidash with Toxic and breed that onto a female Chimchar/Monferno/Infernape for a baby Chimchar with Toxic. + = + = Male W/ Toxic + Female = Baby Male + Female = Baby W/ Toxic.
2). Breed a Male Roselia with Toxic to a female Cubone/Marowak until you get a male baby Cubone with Toxic and breed that onto a female Squitle/Warturtle/Blastoise for a baby Squirtle with Toxic. + = + = Male W/ Toxic + Female = Baby Male + Female = Baby Squirtle W/ Toxic
3). Breed a Male Roselia with Toxic to a female Cubone/Marowak until you get a male baby Cubone with Toxic and breed that onto a female Charmander/Charmeleon/Charizard for a baby Charmander with Toxic. + = + = Male W/ Toxic + Female = Baby Male + Female = Baby W/ Toxic
Hope this helps!