You could probably do all of that with libopenmpt. I'm not aware of any current, maintained module players written in Java, so if using a native library for the "heavy lifting" is not an option, you'd probably have to write most of that code yourself - in which case I'd suggest to stick to IT rather than MPTM files, as there are less features and less corner cases to take care of. It sounds like you will only need the basic parsing of the module format as you want to trigger samples using some other way - that shouldn't be too much work to write in Java. In the end, the amount of effort you should put into this probably also depends on whether you want to work with a fixed set of modules / assets or if they are e.g. supposed to be user-replaceable. In the former case, you only need to implement the absolute minimum amount of features required to get going, otherwise using a more complete implementation like libopenmpt would probably be a good idea.
