I have several friends with twins. I'm always at pains to avoid saying 'the twins' as I have heard it is a no-no, stops them from feeling like individuals etc.
But it seems stilted to say 'x and x', instead of 'the twins'- when that is what they are: twins. If a friend has 2 or 3 kids of different ages (or indeed if I'm talking about my two) I'll say 'the kids' if talking about them collectively, not name them individually. If a friend has two boys I'll say 'the boys' etc.
And when we were growing up we were 'the children', or 'the big ones' and 'the little ones' (four kids with big-ish gap between two oldest and two youngest). It certainly never made me feel like I had no individuality! But then I suppose I wasn't up against the other issues/attitudes twins face. I always thought it would be rather lovely to be one of 'the twins' in our own little unit, though...
Am genuinely interested to hear from twins or parents of twins, as to whether/why 'the twins' bothers them. I'm never sure whether, actually, my friends wouldn't give a stuff if I said it- maybe I should ask 