Non-collinear multiferroics are a new class of functional oxides which produce magnetoelectric coupling by possessing both ferroelectric and ferromagnetic ordering at low temperatures. FeV2O4 (FVO) is a multiferroic which undergoes successive phase transitions at low temperatures. In this study, we investigate the interfacial structures and chemistry of FVO/La0.33Sr0.67MnO3 (LSMO)/SrTiO3 (STO) and FVO/STO heterostructures, in which the non-collinear multiferroic, FVO, is epitaxially grown on both (001)-oriented and LSMO-buffered STO substrates by pulsed laser deposition (PLD). By combining data from transmission electron microscopy (TEM) imaging, and high-resolution scanning transmission electron microscopy (STEM) imaging, the interfaces between FVO and LSMO, and FVO and STO are found to be coherent and semi-coherent due to large lattice mismatches. Energy-dispersive X-ray spectroscopy (EDS) analysis suggests that localised diffusion may occur at the FVO/STO and FVO/LSMO interfaces. Electron energy-loss spectroscopy (EELS) at the FVO/LSMO interface confirms that diffusion plays a role in retaining the epitaxy of the FVO films. However, the exact nature of this interfacial diffusion needs further investigation. Furthermore, EELS studies on the interfaces are required.