My wife and I have a foster son, though our son did not come to us through a fost/adopt program. What I do know is that going through all our training, we were constantly being reminded that the primary goal for a child in the fost/adopt program is to reunite him/her with her biological family, even as plan B (adoption) is being put into place. (Plan B is put into place to ensure that the child has permanency even if the bio parent can't pull it together to provide that.)
This means that you can have a child who stays with you for a year, and you may have every indication that the biological parent is never going to pull it together, but if the biological parent all of the sudden turns around at the child's year of age, it is considered the best thing for that child to go home with his/her bio parent if this parent has shown the capacity to care for the child. Afterall, the parent and child likely had some initial attachment, even if the parent was abusive. Children who have come from abusive homes still often want to "go home" to their "real"/bio parents. They go through grief and loss and separation issues when they are put in a foster home.
The thinking has changed a lot over time. It used to be that foster children were discouraged from attaching to their foster parents because the reasoning was that this would ease their transition should they leave. In fact, sadly, if the children began to show signs of attachment, they were pulled from their homes and moved. Talk about encouraging attachment disorders!
These days, even the most conservative foster programs encourage foster parents and children to attach. What they have found is that if these children return to the bio family, their ability to re-form an attachment to the bio parent actually increases proportionately to the level of attachment they had developed to *someone,* *anyone* (including foster parents) during their time in foster care.
However, the different programs vary a great deal in terms of how it is deemed acceptable to form that attachment. Usually, for instance, they do not allow co-sleeping with even young babies. There is a line in my foster parent training manual, which is also the training manual for fost/adopt, that says, "DO NOT bring your baby into bed with you." And after the child is one, his/her crib must be in a different room.
Our trainer said she bought an overstuffed recliner chair and would sometimes sleep in that chair half way through the night so she could hold her foster children when they needed her at night. But the children can never get into your bed and you can never even sit on their bed (the idea being that we need to reaffirm that their bed is private space, especially for children who have been sexually abused).
One of the most difficult things about foster parenting, especially foster-to-adopt, is that you must parent these children in every way, but you can not necessarily do it *your* way (for some things, I'm thankful about that...I am very glad that it is against the law, at least in WA, to spank a foster child...but rules about co-sleeping with young babies just seem so terrible to me). So even though this baby may one day come into your arms as yours, with "free to parent him/her the way you wish" clearance, until that comes through, I have a feeling that they would frown upon something even as beneficial for the child as breastfeeding. I suspect they would also have concerns about potential disease spread, as ill-founded is that may be. We have a box of protective gloves for putting on bandages, and I can only imagine their notions about disease and breastfeeding!
The only good news is that this, and keeping your foster child out of your bed, and all the other rules that seem so terrible for the child, may serve to some degree to protect your family. For instance, if your foster child comes in the morning in your bedroom to visit, if you don't let him/her on the bed, you are less likely later to be accused of possible child abuse because of some misunderstanding. Our trainer said, "it's sad that we have to think this way in this world, but we do. And once you get that accusation, you just feel icky and marked all over, even if the allegations are deemed unfounded. It's just the worst feeling."
So I guess, in summary, you could check with your licensor just to feel it out, but my feeling is that unfortunately, breastfeeding a foster child, even if adoption seems likely, will not be considered feasible.
Good for you for foster/adopt though! There are no children who need us more!