There was considerable actor crossover between "Warehouse 13" and "Eureka'. Not only did Allison Scagliotti appear on Eureka as her Warehouse 13 'Claudia Donovan' character but Neil Grayston appeared on Warehouse 13 as his Eureka "Douglas Fargo' character. In addition Erica Cerra (Eureka's Jo Lupo), Joe Morton (Eureka's Henry Deacon) and Niall Matter (Eureka's Zane Donovan) appeared on Warehouse 13 as other characters. Cerra and Matter were husband and wife con artists and Morton was a prison preacher. Likewise Saul Rubinek (Warehouse 13's "Artie") appeared on "Eureka" as Dr. Carl Carlson.
The first-season episodes were not aired in the order intended by the show's creators. This is suggested by the episodes' production numbers, which are displayed on the Sci-Fi channel's Eureka website next to episode titles quite often. There are some small inconsistencies when watched closely, but such inconsistencies are minimal and were intentionally controlled. In podcast commentaries with the show's creators and star Colin Ferguson, they confirm that the production order is in fact the order they intended the show to air, but the network executives changed the order to try and place stronger episodes earlier in the run as to help attract viewers. As such, the creators were able to make minor changes in editing and sometimes ADR dialogue in later episodes (such as removing the explicit mention of Zoe's first day at school) to try to eliminate audience confusion.