I adjust pH for clones, just cuz they seem a little picky, but you can sprout a seed in a mud puddle so eff em...they get no adjustment...and they are all always fine...
So you don't have to pH for seeds, and I never have...
I have and have not adjusted the pH for clones, and I find that there is very little difference...but I use a cloner so I need the water in there to be useful and proper for the rooted plants the clones soon will become.
I am not sure if that kinda answered your questions or not...
but the pH doesn't matter too terribly for things without roots...unless it is super crazy...I mean things with a really really low pH can eat through other things...but we aren't talking about a natural pH you might find in your everyday water...I am thinking like battery acid...so that kind of a whacked up pH would be harmful...but whether it is 5 or 8 seeds will sprout...I have tried in near both...I don't know if you can sprout a seed with water with a pH of 3, or 10, but I know most water falls into the 5-8 range, and that is totally acceptable for plants in soil, and any seeds or clones, at least early on...
Sweet Jesus I talk in circles...anyway...that is it.