Hello, I am wondering if I have a Temple Garden in play as well as a +1/+1 counter on Incubation Druid, would I be able to tap the Druid for WWG, or GGW, instead of only GGG or WWW?
No. If there is more than one type of mana that lands you control could produce (C.R. 106.7), and you tap Incubation Druid for mana, you choose one such type of mana (C.R. 608.2d), and all of the mana you add this way will be of that type. Note that Incubation Druid's first ability doesn't say "... instead add three mana in any combination of types that lands you control could produce" (compare Incubation Druid with Axebane Guardian and see also this thread).
In this scenario, therefore, if you tap Incubation Druid for mana, you can add GGG or WWW, but not GWW or GGW (C.R. 305.6, 106.7).
No, you can only add GGG or WWW in that scenario. Incubation Druid's activated ability has you pick one color of mana that one of your lands can produce to add, and it also has a replacement effect that causes it to add three mana of "that type" instead if it has a +1/+1 counter. Therefore, its activated ability can only ever add one color at a time.
In this scenario, therefore, if you tap Incubation Druid for mana, you can add GGG or WWW, but not GWW or GGW (C.R. 305.6, 106.7).