To get all the starter Pokemon, you will need Honey and must have access to Veilstone City. Having Fly makes this easier. Put the Honey on a tree and wait six to twelve hours, then return to possibly find a Munchlax. Catch it if it appears, or repeat the process if it does not. Note: Make sure it is a female. Once you have a female Munchlax, evolve it via friendship. Once you have a Snorlax, give it a Full Incense (obtained in Veilstone City) and place it in the Daycare with any Pokemon on its egg list; some of which include Bastiodon, Sheildon, Cranidos, Rampardos, Snover, Gible, Gabite, or Garchomp). Note: Its egg type is "monster". When you return, there should be an egg. Take the egg but leave the couple in the Daycare. A Munchlax will hatch from the egg. Repeat the process to acquire more Munchlax's. Then, go to GTS in Jubilife City and put the Munchlax up for trade. You can put him up for any Pokemon; people tend to give starters for them. Note: This also works with Pokemon Leaf Green or Fire Red with a Snorlax and Pal Park available.