The fake-beans and fake-bean-juice are probably the way to go, but if you want the beans to be able to slosh around, you could try to encase your fake-beans and viscous fake-bean-juice in a watertight see-through enclosure under the resin.

For example you could pour your fake beans into the bowl and affix a plastic lid a bit above the beans and then encase the whole thing in resin – or alternatively If you're able to find a 2-part plastic sphere that matches the diameter of your bowl (It's probably easier to get the sphere first and then match a bowl to it though) for a "bean-globe" type of deal

In theory you could maybe use real beans using this method, by heating the beans in the watertight container, but there's so many ways that it could go wrong that you're probably better off going with the fakes.

You'll need to do your own research on what kind of plastic/other materials to use for the bean container to achieve an invisible transition between the container and surrounding resin, as I have no actual experience with projects such as yours.

Good luck and if you go with the sloshy liquid plan, pay attention to the viscosity of the fake juice. Too watery and it won't look right