pt-table-checksum with slaves using non-standard ports
The issue is that the replicas don't report their ports to the master.  By default pt-table-checksum tries to connect by filling unknowns with defaults; if the unknowns aren't using defaults, this will fail.  In this case, there are two options:

1) Use the --recursion-method option to change from inspecting SHOW PROCESSLIST to inspecting SHOW SLAVE HOSTS, and configure slaves to report their host.  I don't recommend this.

2) I recommend, instead, that you use --recursion-method=dsn and create a table full of DSN (data source name) instructions that tell the tool how to connect to each replica.  If this table is foo.bar, then you will use --recursion-method=dsn=D=foo,t=bar.

This is only available in the 2.0 series of the toolkit, but you should be using that anyway, because pt-table-checksum is hugely improved in 2.0.