Natural lavender essential oil is a complex mixture of many chemicals, some of which are serious allergens.
There are recorded cases of people suffering skin damage by putting essential oils in the bath. They do not disperse, and although they are not actual 'oils' they do tend to sit in a layer on the top of the bath. You sit in the bath, and the essential oil touches just one area, and causes burns or allergic reactions.
Lavender (and also tea tree) oil are both massive allergens. Both come with serious EU health regulations and limitations attached as to the concentrations allowed in a cosmetic skin product.
My particular worry over a baby wipe is that it is used on an area of skin that may already be a little sore and even broken. This is the perfect condition for a lifelong sensitisation to occur. I am pretty sure that no medical authority anywhere would be OK with the use of lavender in this instance, particularly when as OP says, there is no way of knowing how much or how concentrated the essential oil is on any given wipe.
I used to have a toiletries manufacturing company, and used only natural essential oils as scent materials in my products. I had to follow far more draconian safety regulations because of those essential oils than for any other ingredient that I used. My scent formulas with their concentrations needed signing off by a toxicologist and had to be kept available in case I was contacted by a hospital in an emergency. This is true for all cosmetic and toiletry products incidentally, my company was not special...
The real safety issue with essential oils is that people perceive them as 'natural' and therefore safe. They are not. These oils do not occur anywhere in nature in the sort of concentration that they are in a bottle - it takes for eg kilos of lavender to make a small bottle-full.