I wrote an article on cleaning hoses that may be of some use, and here’s a link that outlines different cleaning formulas and typical max temps/concentrations for different hose liner materials.
Any time you have an oily product and a non-oily product it’s best to keep the hoses separate. Clean the hose, scrub it, and keep it in good shape, but the oil will stick and—depending on what type of oil it is—will typically shorten the hose’s lifespan. Some fats and oils are quite aggressive on hose elastomers. Folks that work with both oils and spirits—say, a facility that produces both wine and olive oil—know that cleaning something well enough to prevent cross-contamination is a fool’s errand, and just keeping the products completely separate will pay for itself quickly in time spent trying to completely remove all traces of oil.
As far as the hose sponges (or “pigs”, as some folks call them), they’re brilliant. A small air diaphragm pump should push through, though how quickly it will push is a matter of its GPM rating and its max PSI. One customer I spoke with just uses compressed air to push the sponge through a wet hose, so that could work as well. Sponges are best at cleaning stuck-on solids, though I imagine they will have a noticeable effect on oil. Using the sponge after chemical cleaning and just before final rinsing will likely yield best results.