2. When trying to check for updates with a missing wyUpdate.exe (which is the case in my dev env) [...]
There always has been an unclear error when wyUpdate.exe or client.wyc is missing. We'll be fixing this in the next version that states exactly what is wrong.
1. The KeepHidden property is not being honoured when forcing the update check (refer to AutomaticUpdater#ForceCheckForUpdate:1255)
You're right, sorry about that. We'll have that fixed for the next version.