Slow growth-Any ideas

big pot, tiny plant is difficult to water properly. good chance that is related. Never worry about whether you 'treated them exactly the same'. All that matters is that a couple are not behaving correctly. It doesn't matter if you feel you treated them all the same, clearly 2 are not acting right. You react to behaviour. Don't worry about what you think "should be", because that doesnt' matter a bit. The soil that sat in a dry spot had a chance to become hydrophobic. If you are getting drypockets in the suubstrate, that could impact the plants drastically. If the potting soil was extra dry and it was difficult to saturate, then it became hydrophobic and likely part of the problem here. if the water "sunk" in easily and like normal, this is ruled out. it's going to stay wet longer than you want - which isn't optimal. You need to water a smaller column around the plant, but make sure that water absorbs all the way down (a little runoff, or 10% runoff with soilless). You may water a small circle around the plant at the top but that moisture will spread out, so even doing so you still have WAY too much substrate that is wet and no roots drinking from it. In soil this is a real risk of creating a toxic substrate if fertilizing too early or too often. An initial charge is fine, but don't dump more nutes into that substrate until the plant can drink it fast enough otherwise you are just adding more mass of nutrients that isn't being drunk and it piles up before roots have spread out enough. in future use seedling pots and up-pot as the plant grows. It avoids numerous risks and hassles. Even with autoflowers. "Up-potting" is not stressful. I've yet to see any shock from doing so with hundreds of plants. it's a misguided common belief.