If your bub really really doesn't like a teat, maybe a small cup (medicine cup or shot glass) could be an option. Medela also make the "Soft Cup Feeder" that attaches to a bottle and delivers small amounts of milk that is managable for bub...maybe an ABA breastfeeding counsellor would know more about these as they are specially for bubs who have breastfeeding difficulties, and to avoid nipple confusion and then enable subsequent successful breastfeeding. They are pricey but might be easier for a child care worker to deal with? (link to look at them is Soft Cup Feeder)
All the best - my son was exactly the same and it ended up being too traumatic for all of us, so I decided not to return the casual work I was considering.