Well it's completely a personal choice how 'dependent' or 'independent' you want your baby to be from you, and also depends on the intensity of your jobs, your ability to multitask, etc.
I will say that MOST people I know who work from home found it almost impossible to get work done with their babies around, especially as they hit the 1 yr mark. But, I (and one or two others I've talked to) managed to make it work and am pretty happy with it, so it's worth a try if it's something really important to you.
I always just nursed DS while I worked. If you want to try that, you can either take breaks to nurse (depending on nursing frequency) or wear your baby in a wrap/carrier and just work while nursing her. It will probably take some time for you to figure out how to do it ergonomically -- which is pretty important if you're going to do this on a daily basis. And your baby is at an age where it might be too hard to work while nursing, hands everywhere reaching for your keyboard or whatever, or may vie for your attention if you're distracted.
So what I would do (adjusting for whatever schedule your kids nap on!) is go over at 9am, work for 2 hours, then your friend works for 2 hours. Then you both take a break at 1pm to get the kids to sleep & resuming working throughout nap. If your kids take 2 or 3 hour naps, you'll be done by 3:30 or 4 the latest. I would also stay flexible from day to day, and if you can work 5 hours one day because baby took a long nap, DO IT. Get ahead on hours whenever you can, because some days things just won't go according to plan and you will only get a couple hours in.
The downside of you both being right there, is that if your baby is having a horrible day (teething, for ex.), it will be very hard to just leave her with your friend while you are just steps away, can hear her crying, etc. So you either need to be kind of ruthless, let your friend comfort while you pretend you're not in the house at all, or plan for the times when you might just drop everything to comfort your baby. You'll want to talk about this so you're on the same page and can both enforce whatever arrangement you agree upon.
Do you both have partners at home? Another thought, at least while you're getting used to this, is planning just to work 2 hours while you're together, and then fitting in your other 2 hours at home while your daddy spends time with baby, or after the baby is asleep for the night.