First off, this classic thread has great information:
A DLR Guide for WDW Vets. Lots of fun reading there!
1. The Information Kiosks (marked by dark green umbrellas and CMs wearing plaid) can be found on the paper maps and the app. The easiest one to find in DL is at the Hub (by the Adventureland entrance), right by the Jolly Holiday Bakery -- this one has the ride board with wait times. There is one outside the exit to HM. There is one between the Dumbo ride and Casey Jr. Train in FL. One in TL by Store Command. You can always go to City Hall.
In DCA, easiest one to find is at Carthay Circle, right across from CCR and by the fountain. This one has the ride board with the wait times. There is one right outside Cars Land. There is one on Pixar Pier by Jesse's Carousel. And you can always go to Chamber of Commerce on BVS.
2. Not sure about this, although I've heard it can be done. I always use the kiosks, CH, and CoC.
3.
DAS can be used for all/almost all rides. I've been told that it can't be used for the DLRR and for the Main Street vehicles, but we've never needed to use it for those anyway. Those lines are usually not very long. DAS works for all rides in FL.
4. No DAS for F! or WOC, but there are HC viewing areas for both shows. Ask CMs about this -- it depends on your situation. For example, if you have a F! dining package and need to remain on your
ECV or in a wheelchair, I understand that CMs will allow you to stay in the last row of the reserved area -- where you will have a very good view and not block anyone else's view. WOC has a designated HC viewing area with bench seating. You will still need a WOC FP for entry to this area.
Hope this helps. Have a great trip!