The plants are looking good in my opinion.
Not sure if the pots *have* to be that big though.
If I read correctly, you acquired clones.
Then vegged for a week or two ?
Three gallons would be perfect IMO.
I've been getting my advice from a grower on IG.
He works for a recreational licensed grow op.
They're growing monsters in 3 gallon pots and killing it.
His pics were amazing.
If you're worried about the soil...
You can always check the run off.
Use RO water with PH 5.9 and water the plants.
Grab the water from the bottom that goes through.
This should tell you 75% of any potential issues.
That's what he recommended for me.
He seems very knowledgable and I sent him a gift card (through email) for his time.
I don't think you will have any major issues then run.
Looking forward to seeing you crush this grow.
Sending good vibes your way...