Agumon would be pretty similar to the original. Fire for that stage and Geogreymon, Fire/Steel for the others.
Gaomon, Fighting -> Gaogamon, Fighting -> MachGaogamon Fighting/Steel -> MirageGaogamon Fighting/Steel (same for burst mode)
Lalamon, Grass -> Sunflowmon Grass/Fire -> Lilamon, Grass/Fairy -> Rosemon (and burst mode), Grass/Fairy
Falcomon, Dark/Flying for all stages
Kudamon, Normal -> Reppamon, Normal -> Tyilinmon, Normal/Flying (maybe Dragon, but he only seems to look like a Dragon and nothing more) -> Sleipmon, Normal/Steel
Kamemon, Water -> Gawappamon, Water -> Shawjamon, Water/Fighting
Piyomon, Fire/Flying -> Aquilamon, Normal/Flying -> Garudamon, Fire/Flying