This concerns f5.com, a large website with navigation menus that drop down when hovered over. The sub nav items (example: “DDoS Protection”) are not cached by Google and therefore do not distribute internal links properly to help those sub-pages rank well.

Best option naturally is to change the nav menus from JS to CSS but barring that, is there another option? Will Schema SiteNavigationElement work as an alternate?

Neither Apple nor Google straight-out give you keyword data in their consoles. However, there are a few workarounds.

Apple has recently added "Apple Analytics" that give useful data, including device types and referring sites. They likely may add KW data in future.

GP (Google Play) does not report keyword data in the Developers Console but (surprise!) when connected to one's GSC (formerly known as WMT), all sorts of juicy data (including keywords) is viewable in GSC. 
http://googlewebmastercentral.blogspot.com/2015/05/rolling-out-red-carpet-for-app-owners.html

App Annie is very useful for competitive research. It's the best tool out there, followed from a distance by Sensor Tower, App Figures and others. But the best guestimate for volume they offer is "Results" for an app store search, which just means how many apps show up for it. Sensor Tower has a guestimate volume based on the AdWords KW tool.

This post from Distilled mentions that SEO for Excel plugin has a "Indexation Checker":
https://www.distilled.net/blog/seo/awesome-examples-of-how-to-use-seotools-for-excel/

Alas, after downloading and installing, it appears this feature was removed...

Unfortunately none of these tools give accurate info. I know because I compared against my own campaigns. Had a SPyfu paid acct for years and it is a useful tool, but not for quantifying adspend.

This was kind of helpful:
http://searchengineland.com/tips-for-spying-on-your-ppc-competitors-89988

Any other advice out there?