My son is 5 1/2 and my daughter is 20 months.
The Octonauts set is a bit disappointing. The 2 figures (Kwazii and Barnacles) are not easy to set so they stay on their legs. They just keep falling. But the Octopod is nice and quite large. Plus you can buy other set and you kid will have his own Octonauts world to re-create his favorite TV show.
I highly recommended the Petitcollin doll. My daughter just love her so much. She keeps it in her bed and we bring her with us when we go away. The doll is cuddly and soft and has a sweet calming scent of vanilla. She comes with a handy little bag to carry her. You can remove her little coat (it closes with scratches). A really good buy.
Playmobil sets are a no brainer: hours of fun, high quality and not made in China. in our family playmobil are as popular as Legos.
The board game is a nice choice for young kids. Very easy to play and fast too. A game is less than 10 minutes so you can play a couple and they don’t get bored.
We also go some Legos (see my son’s Christmas Lego List here: The Best Legos to Give at Christmas)