This wont be an infomercial, well sort of. Teflon hoses are impervious to ethanol fuels as well as most all other chemicals in use today. Thats one of the great things about teflon. The Original rubber hoses supplied by Rotax and other kit manufacturers hopefuly by now have been replaced by teflon. We had our teflon fuel packages as early as 2012.
The automotive industry figured out about rubber hoses and ethanol in the early 90s when some unfortunate incidents occured. When I was in the automotive/industrial fluidline business we saw a BUNCH of these. Nit many people were using teflon at the time, but it became the go to repair for these vehicles.
So, yes, converting to teflon can get costly to do it right, but you dont have to do it but 1 time.
Tom