As the other posters mentioned, the conditions your children have are not important.
Cast members (CMs) are not probably going to know what scoliosis is or what impact being born with that or without an esophagus has on being able to wait in line.
There are people with scoliosis in full body braces and people with feeding tubes who do not need
DAS. So, your task is to explain why and how these things affect your children's ability to wait in the regular lines.
The accommodation provided by DAS is bring able to wait
outside of lines. So, whatever explanations you give to the CMs in Guest Relations need to relate to waiting in lines.
The CMs in Guest Relations at the parks are the ones who issue DAS, so no one here or anywhere else can tell you whether or not DAS will be issued. We
can tell you for sure though that chances of being issued DAS are less if you are not able to explain the
line related needs in a clear, concise, plain language.
Here is a thread that has helpful information - just read the first post. The thread was started at the time DAS was going to begin and most of the pages are from before or soon after it began. The first post has been kept updated, but any of the other posts may be outdated.
http://www.disboards.com/threads/dl...-1-update-12-7-14-das-tied-to-ticket.3179460/
Also, the reasons for changing were much more than abuse by people without disabilities. That was a
small part of the reasons. Other parts included that many people who DID have disabilities were using GAC as a personal, non-ending Fastpass. That made waits longer for everyone.
As another poster mentioned, there were also just too many people with disabilities to keep doing the same thing with access.
When lines strictly for people with disabilities sometimes ended up being longer waits than the regular lines, that was evidence that they needed to make some changes. The DAS system that the Disney parks changed to is very similar to the system used by Universal and other Theme Parks in the US.