Yes, SaasLand is compatible with WordPress 5.0 and higher versions.
After the 6-month period is over you can buy extended support. You can buy extended support in the beginning, too. I that case you get a 1-year support in total.
Yes, SaasLand comes with ThemeForest’s standard 6 months support. We conduct the support via theme’s “Comments” section and also our support ticketing system.
SaasLand comes with “Elementor” which is a very advanced, drag-n-drop page builder. For Elementor related issues, you may check their support: https://elementor.com/support/