I'm pleased to see toilet training was a longer process for some of your dc.
I think this is the route ds is taking too 
We are on day 11 today.
I have to take ds every hour myself and put him on the toilet or he just wees his pants a bit, he initiated once or twice last week but nothing since. He had 1 day were he went 2 hours in between a wee but it seems I've noticed a pattern - his pants will be dry for an hour then a small damp patch appears if I leave it any longer than say 1 hour / 1 hour 15 mins.
He seems to have a small wet patch each time I take him to the toilet, it's as though he knows he needs a wee and he's letting a few drops out then stopping himself and I think waiting until I put him on the toilet to finish it off.
When he has a drink that's the problem! the wet patches appear not long after so I change his pants then another patch appears and so on.
I must say though (he wears a pull up for bed which I put on right before he gets into bed) & it's been dry 2 of the mornings, this morning it was dry and I put him straight onto the toilet and he did a really big wee.
Basically what I'm trying to say is if I didn't have to give ds a drink I think he would be trained by now 

Poo is better. That's in the toilet most times... unless he's being defiant when he needs one then it's deliberately anywhere but the toilet!
It's not all plain sailing, but I think we may be on the right track? LOL