I've been doing a few doodles and researching the kind of names used for locations in existing cities. The names of Tsolyáni Emperors are popular for things like gates and major thoroughfares.
My thoughts on what the towns might look like are currently as follows:
They are focused primarily on commerce and travel. Clans related to transport - whether by porter or chlén cart; shipping; provisioning; wheelwrights; and entertainment of various kinds predominate. High clans might maintain small clan houses for their members to stay while travelling. Administrative buildings are small except those required for commerce and travel related needs. Temples restricted generally to small shrines as is the case in Sétnakh (see "Seal of the Imperium" Vol 1 No 1.)
Metlán - the larger of the two. More up-scale. River Police maintain a small barracks and wharf. Most of the nicer clan houses are located here. Hostels are more up-market as well. No permanent slave market. Small temple to Lady Avanthé. A number of clans run ferries across the river, competing with each other and with clans from Jáyo. The ferries are stratified like the hostels with most of the up-market ferries operated by clans based out of Metlán.
Jáyo - smaller and seedier than Metlán. Has a small but permanent slave market. Largely devoted to entertainments. The temples of Dlamélish and Hriháyel are well represented. Neither town has a proper "foreigner's quarter" but Jáyo itself is such a mix that it essentially serves this purpose. Generally speaking high status travelers prefer to travel through to Metlán rather than spend the night; unless, of course, they are given to hedonistic pursuits! The "House of the Emerald Curtain" caters strictly to those of high standing, with the House Guards roughly turning aside any who don't "make the grade."