A: Yes, if you activate or inactivate a company in Fortnox it will be changed in Upsales as well. The same goes for company status in Upsales as well, if it's inactivated/activated it will be updated in Fortnox.
From Upsales to Fortnox, this applies to companies that are already linked to a customer in Fortnox, which means the company has a Fortnox customer number in the field Kundnummer. A company gets linked when it is imported from Fortnox, or when an order for it is synced to Fortnox.
In Fortnox Premium, if Inaktivera synk från Fortnox is ticked in the app settings, changes made in Fortnox, including status, are not synced to Upsales.