In reply to Tall Clare: Ha, yeah, we have cream carpet too. Doh! If you're quick and thorough it won't stain permanently though, and you might have to accept that she'll have a few accidents along the way. Personally I think interrupting her is a really powerful learning opportunity - on one hand when you praise her going outside it reinforces that that is a *good* thing. But it doesn't tell her that going in the house is bad. Interrupting and following up straightaway with a demonstration / reward for the right behaviour gives her a chance to learn that going in the house is bad, without any unnecessary trauma.
I hear you about the cats. It's a question of socialisation, so regardless what behaviour is demonstrated - excessive chasing, play, fear or aggression - the principles are pretty similar. I'd start with the pup feeling super-chilled out, so toward the day's end sit on the floor with Lotta, and give her plenty of slow strokes / massage (sounds bizarre but it's relaxing for dogs too). This is really good for bonding, plus it gives you the chance to associate a word with this feeling, which you can use to calm her in stressful situations.
Have a leash and collar on her. Get your partner to bring one of the cats in and just let the two of them be in the same room together. Keep a firm hold of her collar, and make a warning noise (like a growl / bark) if she tries to get up. Pull her back down, and resume slow strokes. Other than the stroking, don't interact with her: have the telly on, and talk in normal tones with your partner. After a while, so long as she remains chilled out you can bring the cat a bit closer (poor cat may feel a bit freaked by this, but it is necessary). Keep these 'exposures' brief but frequent, and gradually up the ante. Once the pup is used to being around the cat while simultaneously 'chilled', you can allow her to perhaps stand - with a firm grip on the leash. Let her sniff but don't allow any sudden movements toward the cat (just go back to the previous stage, with her being made to lie flat).
For my latest pup (7-month old rescue, terrified of new people) I've done something quite similar, and it's working well. He's become calmer and far friendlier to new people since coming to live with us in early Jan. Our only problem now is ongoing separation anxiety - common in rescued dogs and thankfully fairly mild in his case - touch wood.