Can I use Dragonite GX's "Dragonporter GX" attack to place a Stage 1 or Stage 2 Dragon type Pokemon directly onto my Bench?
Yes, you can. Per the attack, you are not limited to Basic Pokemon.
Source: TPCi Rules Team (2018-09-27)

Relevant cards

Note: All applicable cards may not be listed below.
SM75_37
SM75_67