I think as you are two women the situation is slightly different to where one woman carries and BFs both the two babies.
I think if one woman has two babies so close it is exhausting for her body, her eldest is still a very small baby when he or she has to "make way" for the younger...
But where you have two women, one carrying each baby and feeding each baby - or I guess you would both feed both of them? Seems like you could do it without being a great strain on one woman's body and the eldest baby would still be able to be "the baby" because there would be two mums! Quite different to one woman trying to carry and manage two small infants.
However, I am not sure it is a good idea.
Might you not start to feel like two women with two babies living together, though? One baby would be "hers" and the other "yours" in the sense that you would have that primary maternal reln only with your 'own' baby?
Also I think it is ideal - even if you're a same sex couple - to have a primary parent and a secondary parent. Primary parent is the one who is the most involved with the baby emotionally, because having a baby is an emotional rollercoaster. Secondary parent also loves and is involved with the baby but has a wider role of supporting primary parent to manage everything in the background plus the very intense relationship generated by having a small baby. Someone who can say - for example - "its alright to co-sleep - don't worry - baby won't be in our bed forever! If this works for now lets do it" and also "we can go out - baby will be fine with grandma - don't worry" - someone to provide perspective and sense check.
If you are both being primary parents at the same time, that very important role gets lost. Two people trying to be primary parents at the same time with all the emotions and challenges of two babies, and no secondary parent - could be challenging.
I am not saying it would not be possible. Of course it would - single mothers do it all the time and hats off to them. But not sure it would be something I would actively choose.
If you waited, she would be primary parent and you secondary parent, and then second time around it would be the other way around.