MySQL Multisource slave as a master? When deploying MySQL multi-source replication, can the multi-source slave be a master for other 'normal' slaves?

I can't find this particular case covered in the documentation
Yes it can.  The multi sourced transactions will go into the mutli source slave's binlog with the same domain id as it receives them.  To further slaves, it just looks like a single server, the same as any other server.