PM sent.
The "{member_ip}" quick tag can be used for members ip. Also saved in the form logs as well.
Not currently, custom fields support is just in a single column format. Open to suggestions however.
I'm using the default theme standards which are mobile responsive already. Check over the demo board in your mobile, let me know if there's anything not quite right and can adjust.
I'll consider it if there is demand for it. But this is the first time it's been suggested to me I believe.