I think many other people have posted very thoughtful and hopefully appropriate/useful ideas for you.
Mine would be this... say to yourself in a Monty Python-esque voice "I'm not dead yet..." and make as many memories as you can with her now, while your body still allows it. If you are financially and physically able, maybe travel with her a bit, but it doesn't have to be something grandiose even -- you know what your daughter would enjoy more than any of us.
2-6 months isn't a lot of time, and I sincerely hope you have more than that -- BUT seriously, carpe diem, I don't mean that to sound as cliched as it does, but really use the time wisely to give her as many good and important memories as you can.
I think the videos are a fine idea, but you will never be able to make enough to cover every situation and milestone she'll reach, or not reach. Helping her to be a strong, healthy, happy, inquisitive, confident, fearless young woman will be your be gift, and knowing she'll 'be ok' might make things a bit better as your time draws near.
Best wishes to you, and I'm sorry you have to deal with this shit. As a parent with a young daughter myself, I can't even fathom what you're going through