Unlikely to work w/ your current equipment/more info needed
It's unlikely to work with your current equipment IMO As you said, the lacking ports all around are a big impediment.
It will certainly be trial and error to find some type of converter that works properly IME.
When you say "I found a device...", would you mind being a LITTLE more specific? [There are a whole myriad of 'devices' that do audio/video/etc.] <ahem> 8-) Please provide makes/models,etc.
Your life would be massively easier if you could simply find a entry level/budget HTIB. Even most of the really cheap ones have digital audio inputs.