The pellicle will protect against oxidation. Thats why they use a nail in the head, to drain a sample without stirring up the pellicle.
Why did you wax? I didn't do this to my barrel and its going ok, going on year two I think. In fact I need to pull and replace soon.
The idea of waxing is to make the small 20 liter barrel behave more like a 200-400 liter barrel in terms of o2 diffusion. From what I have read it works to some extent.
Perhaps it is an overblown concern and there are enough other influences that the increased o2 diffusion has minimal impact. However it was not hard or expensize. I used about 6 bucks worth of bees wax. Had I used paraffin it would have been like 2 bucks worth. and it took all of 1 hours time.
How much do you pull each time? Are you using a small 20ish liter barrel for your solera?