M.W.
If you go with disposables, make sure you get the pull-ups with the sides that open. It makes changing a poopy one much easier! I know some brand has a "cool alert" feature that is supposed to make it feel cool when the child has urinated.
None of them work with our 2.5 year old who has been "interested" in potty training for a year now, but also doesn't want to fully potty train. I think deep down, she likes the attention. So we work on it, then back off, then work on it. The reason I'm telling you this is because at 17 months I was absolutely convinced she would be potty trained in a few weeks. It just didn't happen, and whenever I start to "push" it, it just devolves. Her daycare provider said she'll get there before she's three (dec.). As of now, she could wear a wet disposable or cloth underwear all freaking day and not care---arrgh! ;)
That said, what cleaning products are you using that he was sensitive to when you tried cloth? Charlie's Soap (available online) is what we use for our laundry and cloth diapers and it rinses completely and is all natural. I highly recommend it for training underwear if you go there.
Good luck! Good for you for encouraging your little guy!