Hi, sorry to butt in was having a read and thought id offer some advice on what i can see!
It is quite possible that they are teething. So keep giving calpol before bed.
Looking at your day though, it looks to me like they are not getting enough A (awake) time between their naps. A lot of babies at this age now start increasing their awake time and moving to 2 naps (my DD was at 2 naps by 6 months with a 3 hour A time between naps. If i were you i would start to aim for a 2.5hr A time and hold for a while and see how you go with that. As an example:
Awake 7am? (not sure what time the bubs wake)
Nap 1: 9.30- 11
Nap 2: 1.30- 2.30/3
Nap 3: cat nap no more than 30 minutes 4.45-5.15
7pm bedtime.
This would hopefully help the nightwakes a little.
A few other questions. Are they too hot, too cold? I take it they sleep in the same room, do they wake eachother from crying?
It also sounds like the dummy is possibly now a prop, you're probably best to have a little change of the routine first though, see if that helps, before you consider the dummy prop sitiation. (They will be replugging themselves in a few months anyway)
It must be soooo hard with twins!! You sound like you are doing an amazing job!!