First, why does snacking interfere with sleep?
Personally I feel you have two different issues going on here.
One is that feeding as part of your sleep wind down will be a habit even if it is at the beginning of the wind down routine and even if LO does not fall to sleep on the bottle.
The other is that frequent feeding at short intervals and frequent spitting up I would take as a sign that your LOs reflux is not under control. Some refluxers like to feed frequently (too frequently) because the sucking action helps to swallow down the acid, they are seeking relief from the discomfort of reflux however they are not necessarily properly hungry or need the food which can lead to even more spitting up.
Feeding prior to sleep is not the EASY routine and not the BW way, however many people on the forums have adapted the routine to suit their own needs or their LOs needs. I would say that if your LO takes his feed better during the WD routine and you want to continue that then I'd suggest you only feed at those times and not again when he wakes from the nap - basically following a 3-4hrly E even if it is at WD rather than WU. It is very common for refluxers to take milk better at BT and in the night (DF or NF), often taking a lot more and being able to keep it down. My own DS was like this and took 2 to 3 times as much at BT and his night feed than he did for other day feeds. I believe it is because LO is more relaxed and finds it more comfortable to eat at this time.
As Marta has said feeding to sleep (or part of WD) can impact on LOs ability to transition between sleep cycles, they begin to look for the bottle again rather than just continuing to sleep so it can effect sleep this way.
When LO snacks they need another feed very soon, and then only snacks again, they do not take a proper feed so are unable to go longer. It is the same if a adult snacks all day too.
What medication and dose is your LO on for his reflux meds? What weight is he?