The main thing to remember is, some babies only need small amounts of sleep and that is fine - just means less Y time during the day! But I've always been a believer that if the nights are good and my children are happy during the day, then there's no point hoping for longer sleep. So yes a short am nap and a mid day nap can be absolutely fine for a low sleep needs child (much earlier than other bubs who do 2 big day naps) and yes, unfortunately, they will drop that early morning nap earlier than others and like PP said, the nap will get shorter and a nap of 1.20 mins is fine for a low sleep bub - it's 2 sleep cycles and that can be sufficient for some. - but that would be as they get older. Keep the night sleep as once naps go, that's what holds the days together. A low sleep needs bub doesn't mean that they don't enjoy sleep, just that they need less to be happy - or they only have a 'set amount' of sleep in them so it's best to distribute it - and mostly it's best to have them do an 11 hour night (11.5/12 nights for some - but for others 7pm - 6am is a good night). My daughter is low sleep needs, but has always loved her sleep and needed it, but would only do a 'certain' amount. That being said, she only just dropped her nap at 3.5 years but her total amount of sleep needed is on the lower side for her age. I would love her to be doing 11 - 12 hour nights but I know that she will probably be a child who now will only do 10.5 hours (maybe slightly more) at night and be fine (she's almost 4) and as envious as I am of other Mums whose children her age will do 12 hour nights, I have to keep reminding myself that she is happy, and copes fine on the amount of sleep she gets. A big sign for Low sleep needs babies that day sleep needs to be reduced is the playing in the cot in the middle of the night happily - so yes, that's normally a sign to somehow cut day sleep.
Emma - I would stick to the short am nap and lunch nap. Once you're on that routine it's quite a good one for a low sleep needs bub. Over time you may find that the mid day nap ends up being from 12.30 - 2.30pm and if the lunch nap gets shorter than 2 hours then it's probably best to cut the morning nap first to 30 minutes, then 20 minutes (over time) as a shorter mid day nap will make her OT by bed. It's quite common that low sleep needs bubs need to up from their nap by 2.30pm fora 7pm bedtime - but not all, so it's about experimenting with things. But that would be awhile off. I had a friend who had a low sleep needs child and she kept up a 20 minute am nap for ages and a 2 hour mid day/afternoon nap and once the am nap went, there ended up being a few days where she would offer it, but she always capped it at 20 minutes. A good tip for waking from a short nap is to get to the child before s/he goes into the next sleep cycle. So if they don't wake at 45 minutes on their own, then go in the room before 45 minutes so they don't go into the next sleep cycle as they can wake really groggy from it - as you've disturbed them and it can sometimes take another 40 minutes for them to 'wake up'. If you end up doing a 20 minute nap when she gets older, then wake at 18 minutes - before they go into the 'deep sleep' as again, it is hard to wake them and they wake up much nicer and more refreshed if they don't go into the next sleep cycle...