Not all seeds are created identical, they are all unique individuals.
The smaller one should catch up soon enough, it looks healthy, so give it a chance to get established and in 2-3 weeks you will be wondering why you were stressed about it at all. The funny leaves are quite normal for cannabis and do not need to be overly concerned with.
In future, plant more seeds than you need, this way if you get a "funny" seedling, you are not stuck with growing it, as you will have a spare or two.
I normally start with 2-3 seeds of each strain I want to grow and only keep the best one to grow right through to harvest.
Expensive yes, but I would rather have the best plants, not second rate sickly seedlings.
The danger with only planting as many seeds as you exactly need, is that if any fail to germinate, this can really throw plans out of alignment, or if you get a weird seedling, then you are faced with either growing it or replanting a new seed and this also will mess up your plans too.
Hope this helps,........
Organoman.