Just keep an eye on them for a week or two.
You shouldn't need to pH the water using all mix.
Maybe the plant strain you are growing naturally produces airy buds?
Possibly, I have grown all sorta but the cheapest since I'm new to growing. These ones were more expensive so maybe will be different who knows
edit: I've done about 7 grows in total now, everytime with 2 plants, I've followed similar process on all and My grow before this one is with the sf2000 light which gave me much better results.
Last time I grow, I raised a question on here and someone provided the grow guide. Hence the change/increase in nutes