I'm also keen to find out what might be in the works for Windows Phone. I currently have a mix of Windows 8, 8.1 and soon Windows 10 phones to the tune of approx 200 handsets.
App support from Bluejeans would be fantastic.
I've tried to use Lync 2013 phone app - I visit the meeting link in the phones browser and select to call in with Lync, and get given instructions to put an address into search like - %%%%%#######@lync.bluejeans.com which I do and it does recognise the user and 'connects' but does not allow any chat, audio or video entry to the meeting from there. I've def sorted my Lync->Bluejeans federation as I can use the lync 2013 app on my win8.1 laptop no worries at all.