Introducing new kitten to one year old cat

(English is not my first language)

Heey cat owners of reddit.

Me and my bf has a one year old cat, that maybe have the "Tarzan-syndrome". She didnt have a mother, but she did grow up with her 2 siblings. Her former owners hand raised them all, so she got very used to humans, and grew up being both outside and inside cat - until we got her.

(We were planning on adopting her sister too, but 2 days before we went to pick them up, she might have gotten run over or smt - they couldnt find her)

We live in an apartment on ground level and with a busy street right out front, one reason I did not want her going outside. Don't know if I need to go too much into dept about our living arrangements, just know she is thriving and has a sort of access to outside still.

We have now put down a reservation on a kitten, and will be picking her up in about 2 weeks. We are ofc planning on doing slow introduction with the cats being separatet in diffents rooms, exchanging smells, feeding near the doors and eventually having them see each other with a smaller barrier. All in time depending on how our current cat is reacting to the new smells and sounds.

Another small detail, after we had brought our current cat home, there was an adult cat often wandering by our window and our cat seemend very intrigued, but we havent seen that cat in about a year now, so since that stopped, she has not been near another cat.

So I think my questien is, if anyone else has had a cat with the tarzan-syndrome or if my cat even have the tarzan-syndrome. And how it might have reactet with other cats? And if ya'll think we are making a bad decision?