believe me its so easy to get these. Nature is the annoying part.
First I use 2 power items to pass on 2 IVs and others from parents randomly.
Then I use the hatched one to progress on my breeding, repeat that 2-3 times to do the final breeding.
And the chances are high that you will get what you want within the first 30-40 eggs ;).(well nature heavily depends on luck, but working out great for me).
Also partly my other IV breeds and ditto is helping me with the breedings ;).
As of now I only did Venusaur.
Because of the easiness of breeding on HG, I got distracted and breeded other things instead.
Got some really good stuff.
Will do extrasensory Cyndaquil and AJ Gatr next after hatching all these eggs...