I would add to try to make the introductions as positive as possible. This might mean querying your LA on 'how they have always done it' and referring to new research and suggesting alternatives. E.g. meeting up with FC relatively shortly after placement. 'Traditionally' the consensus has been that you must wait for a good while before meeting up or you will confuse LO, but more recent research has shown better outcomes when you meet up sooner. Or e.g. suggesting a model where you build up to intros more gradually. I don't know, also what is best depends of course on the individual circumstances and the particular child, however I do know that our intros were less than ideal, and mainly due to our LA's or our child's SW's pigheadedness in refusing to even consider doing anything differently than 'we always have done it that way'.
Some thoughts, to pick out what makes sense to you:
Be prepared for emotional turmoil. It is hard when you can't give your baby the one thing he or she wants (for everything to go back to 'normal', for having their FC back, for being back in their familiar environment).
Think ahead about funnelling. Decide boundaries, discuss them between yourselves, then you can rely on each other to enforce them. (E.g. MIL asking to cuddle baby whilst you nip to the loo - ok or not? Decide on it, then stick to it.)
Your new LO won't need much in the way of 'stimulation'. They will be 'overstimulated' by the sheer fact of being in a totally new environment with strangers. But distraction can be worthwhile; creating a semblance of normalcy for them by doing the same kinds of things they are used to.
Give yourself time to get to really know your LO. But allow for the fact that little people change all the time, and particularly as they settle into new circumstances - you may find yourself saying 'oh I've figured him/her out now' just for something or other to majorly change the next day.
Expect a high need for reassurance/comfort and aim to provide that comfort whichever way works, e.g. food, sleep, routines, whatever, I'd put whatever provides comfort above most other needs such as healthy food/educational value/what have you.
Sing, talk, chat away, don't be silent. This can be hard with a birth baby, you can start feeling as if you are going insane, always talking to yourself, monologues, inane chattering... and even harder with a little one who is actively ignoring you. But well worth it's while.
Remember that your LO won't find something 'new' calming and reassuring. But if you do something specific (sing a certain song, do a certain back rub or bum pat, hold hand, stroke hair, whatever) regularly whilst LO is calm and happy, then they will learn to associate that particular thing with those feelings, and you will later be able to use it to calm and reassure LO.
One thing that really helped me is a reminder that tantrums/tears are a) not something that the child can control, so child should not be punished for them, nor should be told not to have them e.g. 'don't cry'. b) an expression of emotion, and usually not about the particular thing that set them off. c) an OPPORTUNITY. As distressing and hard to deal with as they are, they are also a chance for bonding. The moment when the tantrum has run its course, the tears have stopped flowing, is a moment when the child is particularly emotionally 'open'; the tension has been released and hasn't been built up again yet.
With this in mind, I didn't always feel the urgent need to 'fix' things all the time - the real reason behind the tantrums/tears couldn't be fixed anyway. Nor to avoid the tantrum/tears by distracting, or such (though sometimes this is the preferred strategy, e.g. when you are in the middle of a supermarket and in a real hurry to get to an urgent doctor's appointment, or such). With this in mind it was easier to remain calm myself, to let the emotions/tensions be released, and then to seize that moment of emotional openness to be close and calm and reassuring.