You know I had never heard of a grease trap, reading on them it seems they are only on commercial kitchens here. Which explains why I had not heard about them. I would think the main issue with plants wouldn't be the nutrition but the lack of oxygen when everything gets gunked up with fat.
But to avoid cleaning it out. avoid putting grease down the drain. scrape it all out into the bin before you wash anything out, that's what we do. Yes a tiny bit will still make it but we've not in over 20 years had any issues with fat in drains or sinks.
Plants usually don't rotten apples, or grease, it's the microbes/decomposter that break them down and help the plants that follow after.
There are fungi that break plastic and oil spill so a bit of grease, should be fine. I know that koji, will also digest oil too. And microbes in septic tank also digest grease. I think that as long as some woodchip is added to the mix, microbes will remove it in no time.
I don't know of any plants that have been used that way, but that doesn't mean they don't exist. I would probably start with saponin-rich plants like yucca or soapwort. The saponins will leach into the soil and break down the grease.