Buddypress, Multisite and Events showing up on main domain

you can use shortcode like [events_list blog=x] where x is the blog id or using options page at https://your-domain.com/wp-admin/network/admin.php?page=events-manager-options#general > Display global events on main blog =yes

should be able have their own payment gateway or at the very least paypal email.

you can do this using EMPro and then use site specific activation on both EM and EMPro instead of network activated

actually, it doesn’t matter if network activated or not, each blog in pro can accept different payment gateway information, if they pay on a individual blog, that payment info is used.

if they pay on a individual blog, that payment info is used.

But, if I have it set to display events on the main site and they pay there, is the individual blog’s payment info still used?

yes, individual blog’s payment info should still be used.

no, actually they are not, if you allow events to be viewed/booked on another site, the gateway information used is from the blog being viewed