Gawd she is a bit of a cutie, isn't she!!!
Can I make a suggestion - can be totally ignored. I'd not let Moo and Pearl meet for a few days. Let them get eachother's smells first. Swap bedding around and just let Moo settle - she KNOWS the kitten is about, and will do because of smell and of course seeing her already...But take things slowly.
The day after we got our 2 new cats last year, we decided to let them sniff noses through a gap in a door to the room the new cats were staying in....Except the older of the 2 new cats hissed and swiped at one of your existing cats.....And just over a year later she's only just coming in the house properly again - has been living in the garage[coming in house to eat...Cat flap is in garage] if we'd taken things slower they'd have got on better - cos the one the cat doesn't like is the one that hissed at her.
With Females-females you gotta get things slow, females are moody cows around one another - and we're stupid and have 4females, and not one male to balance it around.
You can ignore this whole ramble I've done, and equally tell me to shove off
, but I just thought I'd mention it.