Um... Xander... We already have the digivices. 
Generally when digidestined are brought to the digital world a phone or mobile device on them is turned into it or they just get it. In my experience with most of them anyway... So you'd likely get a card to make them digivolve in a manner of your preference. I think I explained about the digivices and the form of digivolution in the opening post. 
I will be posting soon, so if any edits need to be made please do so. Sorry I was here to give this information earlier. 
Also if you wanted a fire digimon or a specific type I would have recommended someone.

EDIT: I also feel the need to say that none of us should really need to digivolve right now. Mostly because there is only one champion right now who we should be able to work together to beat right now. Maybe the next champion or two will make us digivolve or if we get separated, but for now we don't need it.