The most obvious source for the Aurora design seems to be this Nuclear B58 proposal where you can see the long cigar-shaped fuselage , the diamond wings, the high triangular fin with the nozzles exhausting along it . Canards and Chemical turbojets are on the other hand, not reproduced on the model. Note that this document must have been classified when Aurora designed the Impetus ! Document : Convair
The rhomboid (diamond shaped) wing is rare. So it is a very distinctive feature of the Aurora kit . This Soviet jet design appeared in the February 1955 issue of the RAF Flying Review . As far as I know it was the only publicized rhomboid wing on jet after the German wartime missile Henschel Zitterochen and before the Aurora kit .
Aurora was very conservative in its representation of the nuclear reactor in comparison with the mock-up of the "real" thing .
The Donkey aircraft concept was illustrated in Popular Mechanics / Mecanique Populaire in 1958 . Because the Impetus seems to use a nuclear rocket engine (no intake) of the most dirty type, this was necessary in order to avoid contaminating airfields..
Here are the parts for the Donkey aircraft . Note the long probe used to dock in the socket at the rear of the Impetus. There is no cockpit detail in this model!