Does the Forerunner 50 allow you to count calories burned without
using the footpod?

I would assume it would (like most HRMs) but this comment on your
website is concerning.

"Garmin Forerunner 50 packaged with Garmin's wireless foot pod lets
you track your running speed, distance and calories burned (only in
conjunction with FOOT POD)"

Also does the FR50 have input for Vo2max/OwnIndex or similar?

Cheers
Alistair