I don't have an answer for any of these questions, but I am very interested to
read the other answers that will inevitably come in.

I will be watching this space.

1. You'll have to look very closely at the various options to be sure you're
getting what you want. For instance, with Appcelerator Alloy you write your
code once using web technologies (i.e. JavaScript), but it does actually
"pre-process" the code and spit out true native apps. Most other tools that say
they do are really just wrappers around a web app, even if that web app runs
locally on the device. And users can tell the difference, even if they don't
know what the difference is. It just doesn't "feel" as polished.

2. Then, again, Alloy is likely your best bet. In my experience, if you can
have one person (or one team) focusing on each platform, it's actually easier
to give users a truly outstanding experience if you just develop explicitly for
each platform (Objective C for iOS, Java / XML for Android)... the more you're
relying on middleware to handle all the true business logic, the easier it is
to maintain this parallel code stream, because you're just building two UIs for
the same HTTP API. If everything must still function offline, however, then
you're stuck implementing all of the business logic in both platforms, at which
point you're likely better off going with a pre-processor, because then you can
maintain a single codestream and let the tool spit out your platform-specific
apps.

3. Neither iOS nor Android have built-in support for WSDL. Mostly because WSDL
is now viewed by most as outmoded compared to REST. However, a quick Google
search revealed that there are libraries available for both platforms. I
personally haven't used any, because all of the mobile development I've done
thus far has been REST-centric.

4. Obviously on Android this will likely be just drag-and-drop if you're
developing a true native app (drag it to the libs folder of your project and
just start referencing the code it encapsulates). On iOS, of course, you'd
probably have to port the library to Objective C equivalents (if any).
Depending on the intended purpose of the library, you're probably better off
incorporating its functionality into your middleware and then let each device
type tell the server to use that library to do whatever it does. If the intent
of the library is to leverage actual device features (i.e. camera, GPS), then
that's of course not an option, so again you can just use it with Android but
with iOS you'll probably have to port it.

5. Both Xcode and the official Android Development Toolkit have drag-and-drop
GUIs for designing UI layouts. If you go the Sencha Touch route, Sencha
Architect has a very nice GUI for doing layout design. While this would likely
be insufficient for the rest of your needs, check out MIT App Inventor: it's an
entirely web-based drag-and-drop Android IDE. It seems to be intended primarily
for developing extremely simple apps, but it's impressive nonetheless that you
can build the whole thing in a web page and it generates the .apk for you.

Hope that helps. :)

Tim explained it very well.

I think Appcelerator is a good choice if you want to deploy for multiple
platforms as you "write once, run 'everywhere'". But it adds a new layer to
your app which you can't control. If they've a bug => you've a bug.

Personally I'm a big fan of native coding (prefered iOS/Objective C/XCode). If
you know the language and the tooling you can get on speed on building new apps
very fast. And you have the best control on the code. Nothing generated.

WSDL is not (any longer) common as Tim said. If you can go for REST => go that
way. Otherwise there are plenty of libraries on GitHub which may help.

Recently I had opportunity to use the following tool from Telerik. Very nice
and productive. We use hybrid app approach as it help us to keep the same
codebase for Android and iOS. There is a free account plan, so its very easy to
evaluate.

http://www.telerik.com/appbuilder

Are you considering the deployment options to companies too Andrew? I'd be
interested in people's experiences on managed devices if they have any. Or is
this for the public app stores? Angry DisneyBots?

I came across this today $59 iOS course. I may try it out.

https://stacksocial.com/sales/the-complete-ios-7-course-learn-xcode-5-objective-
c-by-building-14-ios-7-apps?utm_source=stacksocial&utm_medium=social-twitter&utm
_campaign=ios7apps