Regarding Tao, it can actually be done on reaction to her drive from mid to full-screen (2C gets stuffed at this distance), she'll often pass through you in the process though. Sadly though, a drive CH won't let you get the CH 6a > 2DD > field etc combo, but you can dashup 2C into whatever if you land the CH. Also, if you block 5b and sense a 6b, 6a will counter it, leaving tao at the right height for the full combo.
Now, Araknue is a different manner. The biggest mistake I made when trying to integrate it at first, was doing it too early. Doing it too slightly too early will lead to getting counterhit by arakune, and bad things happen. If you do it slightly too late however, the dive will whiff completely. Again, due to the weird nature of 6a, you'll often be crossed up in the process.
Interesting note about litchi though, I rarely get to play against litchi, so that's good to know.