I have been using the alias client feature for a while now, a word of warning. The only place this actually has an impact on the web interface, is the dashboard, there you will see, if configured correctly, the alias client name, a single entry for what otherwise be multiple entries from the same client, and if you hover over the name, the alias client id. However, if you click on the client name, which is a link to the queries view for that specific client, it will show an empty result. Same thing for the query log view and the long term data view, the alias client name isn't used there.
It's very visible if you define an alias client for the localhost entries, when using both IPv4 and IPv6. In the aliasclient table, create an entry localhost with a unique id, than in the network table, create an entry, using MAC address 00:00:00:00:00:00 and assign it the above used unique id. This will eliminate two local host entries in the dashboard, when using both IPv4 (0.0.0.0) and IPv6 (::). The entry for localhost (MAC 00:00:00:00:00:00) is suggested in group management / clients /known clients, you can add it there, but as indicated, there is no option to add the unique id, use SQL.
According to DL6ER, read here, the web interface simply hasn't been updated to handle the alias client feature, and will not be in v5x...