Any thoughts on what's wrong? [autoflower, detailed]

[NEGreenery]

I got this seedling and as you can see, it looks trash.
Any idea on what's wrong? More specs and details below.

Also sorry for the blurry pics at some parts, I was shaking and holding an exhausting ass pose while taking these pics.

Light used: 240W Kingbrite at 75cm from plant and at 60%
Soil used: A super soil, mostly a mixture of BioBizz Light-Mix, BioBizz Worm-Humus (around quarter of what I used the Light-Mix), Greenhouse Feeding Bio-Grow and BioBloom (both at 2g/L)
RH: 58-70%, only 1 dip to 25 - 30%, but for a short time (maybe 4-6 hours)
Stage of life: Veg, Day 10
Strain: Bruce Banner Auto by Sweet Seeds

It also had these small flakes on them, which is pretty obviously powdery mildew (or not? I'm kinda in denial)

On this pic, I spread one flake with my thumb, held 2 fingers on the bottom of the leaf, and it turned into that... (again, sorry for the blurriness)
Btw, it's a different seedling than the first pic.

Dunno if this matters, but:
1) I used some Great White Mycorrhizae to germinate my seeds.
2) Some mycorrhizae was still on the seed when it had popped out of the soil on day 1-2 and I took the "helmet" or aka the seed shell off of it.
- 2.1) Maybe the trichoderma in the mycorrhizae did this?
3) This was the seedling on Day 3 of veg:

 

[AKgrow]

They are babies! They don't need food yet, and they don't need that much light. I'd say the white specks are calcium deposits from the water droplets that's were on the leaves, after they dried. Overthinking will kill your babies, they need to grow up. Don't feed them until week 2-3 and try not to over water, they are in big pots. Turn the lights down to 25% or get a t5.

 

[NEGreenery]

They are babies! They don't need food yet, and they don't need that much light. I'd say the white specks are calcium deposits from the water droplets that's were on the leaves, after they dried. Overthinking will kill your babies, they need to grow up. Don't feed them until week 2-3 and try not to over water, they are in big pots. Turn the lights down to 25% or get a t5.

Ah, okay.. I might have been pushing them too hard. Glad to know the white specks may be calcium deposits. My water I use does have calcium in it.

Btw, I didn't specify my water too.. I don't use any nutrients in my water, I use some pH Down to about 6.5 and some Mammoth P at 0.08mL/L but that's okay right?
I guess I should just turn the lights down a bit... thanks.

 

[AKgrow]

Feeding Bio-Grow and BioBloom (both at 2g/L)

This made me think you are feeding when you water, which would be unnecessary for baby plants in soil.

 

[AKgrow]

Just take it easy til they grow up a bit. Too much love will kill them

 

[AKgrow]

Also, don't mess with pH in soil. A good soil will take care of itself.

 

[Saul.Goodman]

Careful when you water too. Don't want to get any on the leaves. The lights we use make it easy to get burn spots from water drops and even without water drops in some cases.