I'd ride it out, but frankly I usually don't ph seedling medium either. I use weak mineral water that's at ph 6.1, but have used 7.3 tapwater as well. It just doesnt make a huge difference at that stage for seedlings. I.o.w. I'd give them some more time and nothng else.
The low ph water you gave, did you make a small amount of it and/or let ot stabilize first?
Yeah everytime you transplant a plant, she will take some extra time, even at that age. that's why I usually don't pre germinate with tissues and stuff. It differs per strain too, some can handle it better than others. It also looks better because soil is a much richer and diverse environment.
When growing on soil I would not use rock wool blocks, not saying they are bad, and it's of no help at this point, but I've had a lot of success germinating in jiffy plugs, I use "spongepots" actually, a smaller version. Rapid Rooter is another one. Just had a bad batch of seeds but usually get 100% results in 1-4 days. It's like a sturdy and spongy piece of soil in which they germinate. Let me put it this way: it's like the tissue and rock wool cube in one.
In short, it's definitely best for the plant to plant the seed directly into the (light top layer) soil. Just how nature does it. A downside is that you may waste space and time on planting seeds that don't germinate at all, which you'd notice with pre-germinating.