2 year olds fighting bedtime and NW

[twinmama2]

My twin boys are 25 months and in the last few weeks we've started having some real troubles at bedtime.  For the last year or so they've gone to bed so easily - we go through our routine, lay them in bed and leave the room and they would fall asleep on their own.  Then, a few weeks ago L started screaming at bedtime and insisting that DH or I stay with him and hold him.  J doesn't seem to be having any difficulties, except that the change in his brother is causing some disruptions to him falling asleep.  We've been staying in their room with them until they fall asleep, which can be up to an hour sometimes.  Also, we've started having a lot of NW as well.  Mostly from L but sometimes J as well.  They are up at least once a night and are pretty upset when they wake up.  It will take anywhere from 20 minutes to 2 hours to get them back to sleep.  Not sure what happened or why we fell apart all of a sudden?  Is there a sleep regression or something that usually happens around this age?  Any suggestions?
Our EASY usually looks like this:
6:30 awake  (L has been waking up later than this lately - I think because he's so tired from the NW)
12:30-2:00 nap
7:30 bed (we are thinking of trying a later bed time since it's been taking so long for them to fall asleep??)
Then L is usually up between 12:30am and 2:00am for a while
Someone usually cries/fusses for a bit around 4:30 or 5:30 am but usually goes back to sleep on their own

[creations]

I find there is always sleep disturbance (and behaviour/emotion struggles and developmental leaps) around the birthday no matter what the age so we come to expect it at the birthday and half birthday every year. It could be that and you might find things just fall back into place in another couple of weeks if you hang tight, keep supporting and as things become more peaceful begin to step away a little at a time (either gradual retreat or WIWO with verbal reassurance from outside the room etc).
Some LOs can become a little fearful of the dark at this age (from memory around 2 - 2.5yo, hope someone corrects me if I'm wrong), so you might try leaving a little night light in the room helps or having the door open a crack and have the hall light on, something like that.

Random thought just popped into my head.  Maybe a speech/language development?  We had big ones around 18 and 21 months but some LOs it's a bit later and perhaps with them being twins they are having a big language leap at 24-25 months (I'm not suggesting they are 'behind', I also know non-twins who have had language leaps later)?  The NWs were big here during DS's language leaps.

If it's taking an hour to get them down every night then I would move BT later for several days, as you've said, to see if it gets them down faster (and no loss of sleep as they are awake that whole time anyway) but I'd be prepared to move BT earlier again when this developmental leap has passed.