Most of this post will have nothing to do with adoption, and the parts that do, I hope don't sound too patronising.
We do have a few minor developmental concerns about Baby Spouse but to be honest, most of them are not genuine - he's meeting all his milestones, in the well worn phrase, and is doing just as well as many other children we know, though of course we'd like him to be doing better. There are a few children who are younger and doing things he can't, but with my professional hat on, I know that's OK.
We know from the way he plays that he doesn't have several major developmental concerns. He can tell what we are thinking - and he tries to manipulate that - he will offer you a toy, hold on to it when you try to take it, and laugh. He can tease you, in other words. He will anticipate what you are going to do by lifting his arms to be picked up, by smiling before one of us comes into the room. He does not have autistic tendencies to any major degree.
He's appropriately active for his age, and we knew almost from birth that he didn't have major developmental delay, he wasn't floppy, he tried to move, he learned to smile on schedule; he responds to us talking, and has done all along (though he was quite placid in the face of loud noises, which we think we know a reason for, but we weren't worried as he'd passed his newborn hearing test).
I've noticed a couple of tendencies in other parents which I find a little interesting. One is that, as I mainly know parents of first (and at this stage only!) children, a lot of them are really eager to play with their children in ways that I (and they, really) know they aren't ready for.
Most babies aren't that interested in cuddly toys till around a year old (maybe a bit younger), and then it seems to click - that's been true of Baby Spouse - but a lot of parents of newborns seem very keen to introduce a lovey very early which, actually, could be unsafe if it's a large toy they could get their face stuck in. A lot of my friends took their babies to the park at a point when they found the swings and slides a bit scary (so did we - bit of a mistake!). We all read books to them from very young, which is not wrong, but we have tended to buy books that are advertised for babies - flaps, touchy feely, animal pictures etc. - which they don't really appreciate until again nearer 5-6 months when they can handle/feel things, or a bit older when they can appreciate pictures. This is a very natural tendency as you see parents of older toddlers doing all these things and you want it for yourself and your baby. Especially if you have only a few months' maternity leave, you want to make the most of it and do lots of fun stuff.
The other tendency I've noticed, which is related to play but to new adoptive parents can seem more like care, or behaviour, or battles, is that a lot of new adoptive parents of toddlers have had very little training or experience of what babies and toddlers can and should do. Some of what might be better seen as exploration or trying things out (which I'd include under play) can be seen as poor behaviour, a result of neglect, or of being slightly ignored and/or indulged by foster carers.
A lot of this seems to be around eating - such as putting too much in the mouth, or being incredibly messy, flinging food. Children can obviously revert to slightly younger behaviour, so if they'd fed themselves or grown out of playing with food quite so obviously in foster care, they may revert to this on placement. But it's a stage all children go through and I feel that adopters should learn more about how most children behave and play and should be able to work out what's something they should worry about, and what is perhaps a bit immature but not worrying.
For example, a poster was worried that her 19 month old threw bowls of food on the floor. Another poster said perhaps the child was seeking her attention by doing this. Now, we don't have a 19 month old yet, and I'm crossing my fingers ours will have stopped doing that by then - but we do have a nearly 15 month old and there's no way I let him have the whole bowl of food, ever. He can have a spoon or fork, and some days he uses them appropriately, some days he plays with them. That's how he learns. And yes, he looks at you to see if you noticed, but he does that with everything else he flings on the floor, and more or less every game he plays too. For his age, this is appropriate - food is a game - and it's not inappropriate for a slightly older child who's been unsettled, either.
The same is true of things like asking strange/inappropriate questions, how much children actually understand and remember (and what they are very unlikely to remember so are probably reconstructing). These are all things that come up when children are playing, and that the large number of people adopting under-3s get absolutely no training whatsoever on. It's completely mad.