I don't believe it makes sense and/or I fail to see the logic.
Regarding the first point, this is what I believe I hear you saying
According to your personal definition, the entity cannot survive outside the womb at <= 2 months gestation and is therefore not a baby.
Okay, I dont agree, but I understand that.
According to your personal definition, the entity can survive outside the womb at => 5 months gestation and is therefore a baby.
I have a problem with that because NO fetus, not even one, can survive outside the womb at => 5 months gestation without care. Left alone they will die in short order zero survival rate.
According to your personal definition, the entity between 2 months and 5 months gestation may or may not survive outside the womb whether or not it is a real baby or a non-baby fetus is dependent on the care that the entity receives. So, under one set of conditions (superior care) a 5-month-gestation entity is a baby and under another set of conditions (inferior care) a 5-month-gestation entity is a non-baby fetus.
Again, as with the 5 months or longer gestation, I have a huge problem with this. It makes no sense to define life based on whether of not the fetus is cared for. Obviously, no care equals no survival.
Now to the second point you try to separate if and for how long from your could survive equation. You really lose me here, big-time. I fail to see that logic at all. Look at it this way
You would surely agree that a one-week-old baby, post birth, would not survive without care, correct? Im going to assume that as a given. The same would apply to a one-day-old, post birth, baby. And it would apply to an 8-month gestation entity and it would a apply to a 5-month gestation entity and it would apply to a 3-month gestation entity and so on and so on until you get back to conception. You have a zero survival rate for all fetuses/babies/entities without care.
So, to answer WHETHER or not a baby COULD live outside the womb I can only say that without care the entity CANNOT survive and never will. Therefore, you logically must do one of three things. One, you can move the definition of when a fetus becomes a baby forward to where the entity can survive entirely on its own in order to take the external care factor out of the equation. Two, you can call the fetus a baby from conception regardless of the level of care thereby also taking the external care factor out of the equation. Or Three, you can define the level of external care that makes the difference between fetus and baby.
I believe your argument relies on the third option i.e. dependent upon the level of care available specifically between 2 and 5 months of gestation. That puts you back to a situational definition of a baby dependent upon current and changing medical technology and whether or not that level of care is available to that fetus. I think that is a horrific definition of life.
One more question (which may lead to an additional follow-up): If a fetus (pick any "fetus" period you like by your own definition) could survive outside the womb with readily available care and that care is denied resulting in its death, has a murder been committed?