Pardon my choice of words; soundcard is not appropriate here and perhaps audio interface would have been a better choice of word.
So to recap, the Firewire 410 is a firewire audio interface and the Audiophile 192 is a PCI audio interface.
The Delta 1010 is a "dock' so to speak and is connected to the computer via a PCI card interface.
http://www.m-audio.com/products/en_us/Delta1010-main.html
Why would you need 2 separate interface if 1 can do the job. It is neater and less likely to cause sync problems that can cause clicks and pops.
Do note that you have to set 1 audio interface as the master (and since the Firewire 410 is a 24/96 interface and the Audiophile is a 24/192 interface, you would have to interface them at 24/96 resolution (thereby wasting the spare capacity of the higher resolution of the Audiophile 192).
ps - what are you using the Firewire 410 dock for that the 192 cannot provide? If it's for more audio input, then look at
1) Delta 1010 for PCI type audio interface
OR 2) Firewire 18/14 for firewire type audio interface.
The 24/192 resolution to me is a bit gimmicky. Very few of us here can hear the difference between 24/96 and 24/192, especially if you are recording pop/rock. The only people who are happy are hard disk makers because it takes up a lot more space at the higher resolution, forcing you to buy/upgrade to a bigger hard disk.