Every license of yours works and will continue to work as an entitlement to either use Dolphin Classic or Dolphin U. Mobile License is a part of Prime, but separately it costs the same as a Permanent Dolphin License. We can, should you ever want it, exchange a Dolphin license to a mobile license for you. They are the same value.
I have gathered about 8 licenses over the years and I asked to convert one of them into a mobile license and was told "no". Has this changed, if so I would like to exchange a couple of Dolphin licenses for mobile licenses.
We didn't have the right tool convert for a while, but now we do. You can just email your request to igor.lebedev@boonex.com with reference to this reply/comment. We can only convert "paid" licenses though, not the ones that have been granted for free.
Mobile License gives your the _right_ to rebrand. It doesn't include a rebranding service, since it is more of a creative process that may be very different depending on your personal branding specifics.
Best regards