Sounds fairly similar to what we had done last year. We also had an outside loo which they might have used, it was demolished on day 1!
Don't forget to buy masses of sugar, we went through more sugar than I ever expected
Make lots of tea for them whenever you can and give them lots of nice biscuits.
We were also TTC but I think the stress of it meant I didn't get pregnant till we moved back in so don't have any expectations there. Looking back, I wouldn't have coped if I was pregnant, but if you have easy pregnancies you might be okay.
If you can move out then do. The builders will be much quicker not having to tidy up every night. We were lucky in that we could move in with my parents, which saved loads of rent. We also moved all our furniture into the two rooms that weren't touched, and put extra locks on them too.
Check with the builders at least every week or even every 2-3 days, about what the next decisions coming up are, and make sure you're ready. E.g. exact position of sinks, loos, showers, radiators, doors, windows, sockets, lights etc. Also make sure you have know what plumbing fittings you are going to get as it may affect how they do the plumbing, but check with the plumbers about that. Builders really appreciate if you are always one step ahead on the decisions, it makes their life so much easier and I think it's quite rare actually. Our builders said we were the first clients who didn't hold up a build because we always made a decision in time
Especially towards the end of the build be there as much as you can. Like every day. This is when all the things you will actually see will be put in, e.g sockets, lights, switches, tiling etc. They always do what is easiest for them without using any common sense, and you need to specify exactly what you want. Electricians in particular. We had some crazy positioning of sockets until we marked exactly where we wanted the sockets on the walls, not just the plans.
Get the costs of dealing with any foreseen problems (and there will be) in writing before giving the go ahead.
I don't know how you are dealing with paying your builders, but always make sure you go through every bill with a fine tooth comb as soon as you receive it. We had great builders but they still messed up a few bills. On a couple of occasions they over charged us but we sorted it fairly easily. I could imagine they could have easily been missed if we weren't particularly anal about the itemisation.
Good luck, it will be worth it though.