I saw your thread in Active Convos, and although I should say I don't have twins, I have had two babies (at separate times) and your post made me
I'm afraid.
I totally get that you both want and need to continue your career. That's great, but I think you have very unrealistic ideas about what life with a small baby is like - or in your case, two small babies.
Starting to do some work after month 1 or 2 (even a tiny amount): I think this is bonkers! When both my babies were 4-8 weeks old, I was exhausted. Not only was I recovering from the birth (and in both cases, I had completely normal pregnancies, textbook vaginal deliveries with no intervention or any health problems afterwards), but every single night I was woken up every 2-3 hours to feed the babies, with no chance of "catching up" at weekends, or at any other time. Sometimes you are awake for 2 hours in the night because the baby just won't get back to sleep, or because it's just done another poo, or because it's feeding for 40 minutes, then burping, then won't go back to sleep for another 30 minutes.
Babies are relentless, and relentless 24 hours a day. Every single day. I am an educated person (Cambridge degree) with a professional career, and during both mat leaves I found that sometimes I literally couldn't string a sentence together. Partly due to tiredness, partly due to babies just being all-consuming. There is no way I would have wanted or been able to do any kind of paid work.
By months 3-4, in some ways the tiredness is worse, because you now have 3-4 months cumulative broken sleep. Even if (and it's a big if, as you have gathered) you have dream babies who go in a lovely routine, you will still have broken sleep. I am actually still pretty tired quite a lot of the time even though my children are now 4yrs and 15 months, in consistent routines and sleeping through the night: they wake up every day at 6:30am without fail, the baby sometimes wakes up in the night (teeth, temperature, just letting out a wail and going back to sleep).
On the routine issue: are you prepared to let your babies cry? To go with what you want, rather than what they want? Some parents are ok with this, some aren't. It can be very emotional leaving your own crying baby, even if you think you are doing it for the right reasons (and personally, I think that under 6 months is too early to be doing any sort of formal routine).
I think a lot hangs on whether both your babies are going to slot into a perfect routine as quickly as possible. Even if they do, I'm really not sure if you'd be able to predict regular times when you could, uninterrupted, get on with some paid work. Most new mothers (including me!) find that they can hardly manage to have a shower, do the washing up and get to the supermarket, let alone write a research report on top of that.
You haven't mentioned if you are planning on breastfeeding? I think that's relevant to some of the issues you are thinking about.
In terms of your boss, I understand you don't want to freak him out, but as a boss, I would potentially feel far more let down if a team member assured me that she would be working a bit a month after her babies were born, going to conferences soon after that etc, but then found that she couldn't commit to that once they actually did arrive.
Sorry for such a long post - I'm afraid I just read your OP and thought it sounded rather naive.
This all sounds like doom and gloom, but I absolutely think that it would be possible to resume work, but after a few (a good few!) months, rather than trying to pretend that your life really hasn't changed that much. And you will never ever get these early days with your babies back, whereas you will be able to resume your career after a few months.
Best of luck with the rest of your pregnancy and with deciding about what's best for you - it's great that you are thinking about these issues in advance and I'm sure you can come up with some possible solutions for your family.