Connecting optical ADAT to optical S/PDIF will not work (just because the connectors look the same doesn't mean the digital formats, ADAT and S/PDIF are compatible)
If you choose to connect the S/PDIF in/outs it will work, but not the way you expect: you can only use the 2x2 S/PDIF input/output channels, i.e. none of the real input channels.
You can't get an "ADAT port only" device either. ADAT comes with sound interfaces, so you'd have to buy another one, which kind of undermines the goal here.
You could though get another USB driven interface with ADAT and double the amounts of inputs, like e.g. the PreSonus Studio 192:
It should be possible to find other used "legacy" interfaces similar to the above to a fair price.
If you go looking for other interfaces you need to make sure the optical input/output is for ADAT.
Another option is to extend your laptop (if possible). According to the specifications The M-Audio device requires FireWire 400.
If possible you can extend your laptop with a FireWire PCMIA Express card like this one from Belkin:
(Last option: It should be theoretically possible to contruct a FireWire 400 to USB3 adapter/hub, but I haven't been able to find any.)