Bruno's gorgeous!! Bet you cant wait to have him home with you.
I think as Emmy-Lou has said it's a bit easier to introduce a kitten into a household where you have another cat which is not too elderly or set in their ways (although some elderly cats respond very well to having a kitten around, so no hard and fast rules!)
We introduced 3 month old Moray to 18 month old Tinks, and after some initial horror on Tinks part, and much running away and slinking back again, they got along fairly quickly, which was down in part to the very great wisdom Moray showed for such a young cat, as he seemed to innately know that Tinks needed a softly-softly approach.
Pav, another Purrs member, also introduced her cat Miss Felicity to a young and homeless Mr Jangles, and with similar results in a relatively short period of time - in fact Pav was my mentor and "go to" for inspiration.
It really is a good idea to set up a separate spot for young Bruno, and if you dont have a lot of space, then a cage would be a good investment, as he will learn to think of it as his "safe space" and Bebe will be able to view him in a favourable position, again from her own place of "safety." We made Moray a little den in our spare bedroom. He had his litter tray there and his food and water (never put the two near each other - litter trays should be at the opposite side of the room to any food if possible. Whenever we weren't around to supervise, Moray went into his den, and Tinks had the run of the house. It wasnt long before Tinks would go up and sit outside the door to the spare room, curious about the kitten inside.
For us, the key to integration was taking this steady, and involving both of the boys in regular playtime sessions with the flying frenzy toy - like a wand with a feather attachment on the end of a piece of string. Naturally, Moray as a kitten thought playtime was just amazing, but Tinks became interested too, and would join in enthusiastically - until he remembered he was meant to be sulking, and he'd scuttle off for a bit to watch. Wasnt long before he was joining in again in spite of himself, and I think it took less than three weeks before - eventually - we found Moray curled up next to his new big bruvva, and a look of real satisfaction on his little face.
It looked just like this. Moray's on the left and Tinks is on the right - with the big goofy grin on his face.
We began to introduce joint feeding after about a week, but we always made sure that Moray had a little food in his den anyway, and we would always supervise mealtimes. Thankfully, we had little trouble on that score, and they settled to eating together more or less from the outset of our joint feeding venture.
If you play with and pay attention to both of your cats, respond to their needs, and provide them with love and stability and stimulus (particularly if they're going to be indoor only cats) then they will stand every chance of growing up to be happy, well rounded characters.
If they are indoor cats, then think about trying to provide a good size climbing platform for them to share, or a separate one each, and if it's possible to locate them by a window where they can watch things going on, then that's ideal (but taking care to ensure they cant get out of any open window - and cats and kittens can be wonderfully imaginative when it comes to escape - never think a gap is too small!)
Two litter trays are better than one - three are better than two, but when space is limited, that can be tricky, so you have to try and adapt your home as best you can. Be aware of any inappropriate toileting that may crop up - it can be a sign of stress, and can be a potential problem of sharing one litter tray between two cats. A plug in diffuser such as Pet Remedy or Feliway can help to calm the atmosphere too - they smell like sweaty socks to us, but they can help cats to feel more settled. You can buy them online more cheaply than at the pet shop, but either way, they're not a bad idea to begin with. We had two - one downstairs in the living room, and one on the landing midway between the bedrooms. We only used them for around a month before we felt comfortable unplugging them. Might be an idea to get one, and to plug it in a couple of days before the new arrival comes home.
Cant wait to learn how things go, and dont be shy about asking questions if there's anything that crops up which you're unsure about. Just to reassure you, there are many many purrs members who've successfully introduced cats and kittens, cats and cats, cats and dogs, cats and guinea-pigs, cats and rabbits and so on, with little or no difficulty. They key is in being aware, monitoring introductions carefully and not rushing the process by imposing our impatience on the situation. (And I say this having shed not a few tears myself over our two when we first brought Moray home, but that's a story for a different day
suffice to say, those tears didnt last long, and were as much a reaction to the cat we'd lost, as to the cats we were trying to integrate
)