First, the DA10 is equivalent to the Blue, I'm pretty sure it's the same circuit. The Blue D/A is advantageous because it's slightly less expensive than the Black (by about $125), and it will save on desktop space because it's going to all be in one 1ru rack. The Black has it's advantages because it has a built in volume controller (that tracks L/R more accurately than a pot like on some other units) and headphone output.
The only way to utilize the extra features (volume, headphone) that are found on the DA10, with the Blue, is to buy a seperate monitor controller, the cheapest one being something like the Central Station...so you'd have to spend $400 more (or double or triple more for a higher quality unit) in addition to the cost of the Lavry Blue. Otherwise a straight signal from the D/A into your speakers is most likely going to blow your head off, not to mention no control of volume. You want to keep your speakers or power amps gain all the way at max and control the volume with the DA or monitor controller. However, the DA10 does not have speaker switching, so you'll only be able to monitor one pair of speakers.
If you need to monitor more than one set of speakers, you'll be required to get a monitor controller. Regardless of whether you decide on the Blue D/A or the Black DA10 they will both use their own internal crystal to reclock the signal, so there is no way for you to use the Blue Msync as the master at any time. This is a good thing IME. So you'll just be sending clock to your AES32 card and the Fireface. I would do it like this: clock the Fireface through PLL (the BNC to BNC) and then let the card derive it's clock from the AES input of the Lavry A/D simultaneously. Some other people may have different ways, but this is simple and I know it works and it will only require one single cable (the WC cable). The AES connection should have come with your AES32 card on the breakout snake. Good luck!!!