Yes. You can keep editing a Studio site after launch. Pricing, products, content and modules are all still open while the campaign runs. Chart-sensitive changes are the one group that needs care, and those go through your EVEN team, who keep chart bodies notified.
What you can change mid campaign
Most of the site stays open to you while the campaign runs. Pricing can change. You can add a product variant or close one, rewrite content anywhere on the site, and switch modules on or off as the rollout moves. EVEN configures every Studio around its rollout to begin with, so reshaping it as the campaign develops is a normal part of running one.
Chart sensitive changes
Anything that touches the chart plan goes through your EVEN team. They make the change and notify the chart bodies, because applicable chart rules require that notification. If you are not sure whether a change counts as chart-sensitive, ask before you make it.
How to request a change
Every campaign runs a shared thread with your EVEN team, so flag what you need there. Merch stock is the exception, because you never have to request it. Inventory syncs in real time with your store of record, so the site sells against the stock levels your store reports and nobody oversells.
Orders already in flight
Orders keep moving while you make changes. Your team updates statuses and tracking in the merch dashboard throughout the campaign, and the fan sees those updates in their account.
Deciding what to change
The dashboard updates in real time, so you can watch what a change does while the campaign is still running. Sales and revenue, traffic sources and conversion, fan growth, opt in rates and geography all move live. Those numbers are usually what tells you a price, a product or a module needs to change.