Thanks Spacemonkey. I will post some of my experiences from time to time.
Thanks Swimmingdancer for your advice. You are right, first I shoud recommend an Ayahuasca center. If they still want to do it on there own I should make sure that they are well prepared in every way.

I hope its not to late for you Developingcolor. If you have the chance to go to a Ayahuasca center or church, that would be the best choice. If you still want to do it on your own then both of you be better very very well prepared. read and view as much as possible about Ayahuasca and about peoples experience.
Then one of you should do it first and the other one should stay sober as a sitter. somebody who understands what you are about to do, just to help you out with little things like bringing you to the toilet if you are dizzy etc. However, he or she should not interfere with your process or even panic. The sitter should encourage you to go through the darkness no matter how much you are scared of. Know that ,there will be no danger at any time, no matter what happened.
Just make sure you have a quiet, safe setting where nothing can disturb you for the next 5 to 8 hours.
Further, if you have only 10 g mimosa available, chances are that it might not be enough and it would be wasted if you brew it. On average people use 10g if they brew it properly. As a first timer chances are that you don't do it the right way, just like in my case, I wasted 20 g of brew for no effect, but purging.
If you put the powder in caps, you get 100 % of that stuff. you will need only about 2g for each trip so you would have plenty left for your next sessions. remember it can take a few sessions until you get a break through.
And about the tannins I found out they are not so bad since they are in fruits as well. here is some info I found:
Tannins are naturally occurring plant polyphenols. Their main characteristic is that they bind and precipitate proteins. They can have a large influence on the nutritive value of many foods eaten by humans and feedstuff eaten by animals. Tannins are common in fruits (grapes, persimmon, blueberry, etc.), in tea, in chocolate, in legume forages (trefoil, etc.), in legume trees (Acacia spp., Sesbania spp., etc.), in grasses (sorghum, corn, etc.).
Now let me know if you have any background in Psychedelics. Are you on any medication recently? Did you have a traumatic experience recently? Anything else you could think of?