I pushed an update to trill-twod where you can send multiple touches to the page. To do so, set trillMultitouch = true. Then in parametersFromTrillLocation and the likes, the values will be interpreted as is (assuming you have two elements in the trills vector):

0 -> trills[0] touch 0
1 -> trills[1] touch 0
2 -> trills[0] touch 1
3 -> trills[1] touch 1
4 -> trills[0] touch 2
5 -> trills[1] touch 2
... etc

The rest of what you are asking is quite application-specific so it's best handled with rnbo, or by writing some custom C++ code yourself.