Pressing for more details
about the queue pretty much means what you had already said was either a diagnosis or had not clarified why being in the queue is a problem. Too many people prepare themselves with a list such as "my child's doctor diagnosed X Y and Z, she's in 3rd grade with an IEP, she gets speech therapy and OT at school plus an aide in the classroom helps her stay focused, her OT said we should get
DAS." None of that helps for WDW.
Envision yourself in the queue with your child... then think about what happens... and ask yourself "What's going wrong? What does she need or why is being in the queue a concern? What is the negative aspect and why is it resolved outside the queue?" Keep your request focused on the queue environment and why being outside the queue is necessary (not preferred but necessary).
Mobility devices (stroller-as-wheelchair, wheelchair or
scooter, walker/rollator, etc.) can serve other purposes within a queue. If there is a need to sit down or change position, a mobility device is likely to be the suggested accommodation even if the person can walk.
Sometimes a video or phone CM may not fully comprehend. If you are not successful registering for DAS in advance, try the parks and then go to Guest Relations armed with your recent experience(s) to share and request again. That's exactly what we did on our first visit with DD - tried without, then made the request when things were rocky.
