Now that marvel is going to merge with Shield 6 & Co into X-Pack, will there still be a free basic version of Marvel, or will there be a free basic version of X-Pack ?
Yes, the free Basic license will still enable the same Monitoring functionality in X-Pack that you have with Marvel today.
When we update the subscriptions page to describe X-Pack for v5, we will include a very clear description of what capabilities are enabled with which license level.