As the very crude way do sort out what might work: you need to find solvents with boiling points around ones for Buthyl Acetate and Butanol. Also, due to the nature of the process, the solvents you are looking for, need to be insoluble in water.
The easiest way - do search "MSDS Activator for Hydrographic Printing" it will give you picture of typical blends used in the process. Select solvents from there.
Try ethoxyethanol, propoxyethanol and or butoxyethanol - they should be inexpensive, but do not know anything about their toxicity.