Hi,
Try not to worry too much hun. I will try and answer your questions from my experience, may or may not work the same for you...
When Bren first met Jacob it was when Nick brought him into the hospital to see me. I got Nick to call me just as they got onto the maternity ward so I could put Jacob in his crib as I didn't want to make Brendan jealous from the start. I gave Brendan a big hug and made a big fuss of him (mainly because I had missed him loads!!) and then we introduced him to his little brother. We sat him on the hospital chair and held Jacob on his lap and made a big deal over Jacob being Brendans little brother and how special they both were.
Brendan still sulked with me for a few days but I think that was more down to me leaving him with a friend for two days. He was surprised we brought the baby back from the hospital though lol! :lol:
We didn't do the present thing as he was a bit too young to understand but maybe at Fins age it would work well to have a little pressie on standby to give him from his new brother or sister.
I was only out of the hospital for a night and my mum came over the next day for two weeks so I had help at first which was good as I was really trying to make a go of it breastfeeding and Jacob was feeding every two hours and feeding for nearly an hour at a time!!!
You will probably find the first few weeks are ok as newborns sleep so much. Try and keep Fin in his routine as much as possible and get your hubby to look after the new baby every now and then so you can have special mummy and Fin time.
Have you got somewhere you can put the baby when you are in the livingroom/ kitchen? I have a baby swing in the livingroom which has been fab and a vibrating bouncer which I can move around depending where I am. It means I can take Jacob into the kitchen with me when I am cooking and I can see what Bren is doing to him as he can be a bit rough at times without meaning to be. 
On a morning I usually get up and showered before hubby leaves for work at 7am, otherwise I take Jacob into the bathroom with me in his bouncer so I can keep an eye on him.
Bathtime, we bath them together. Jacob in his baby bath seat at one end and Bren splashing like a crazy man at the other end
I wash them both and then get Jacob out first, we live on one level at the moment so the living room is next to the bathroom so I get Jacob dried and in his pjs and put him in his bouncer, then go and get Brendan. I get them both a bottle of milk and Brendan sits on the sofa next to me or with hubby and I give Jacob his milk. Jacob normally falls asleep straight after his bottle so we put him to bed and then about half an hour later it is Brendans bedtime.
You'll find you soon get a routine around what suits you so don't worry too much.
During the day Jacob will either be in his bouncer, swing, or on his play mat and sometimes Bren and I play with him together, sometimes Bren is busy playing with his toys on his own. Jacob has about three naps during the day so I get time to get a few jobs done or do something with Brendan on his own. If I read a story to Brendan I usually have Jacob on my knee at the same time. You soon get the skill to have two children on your knee at once!
It can be tricky at times, sometimes Jacob really wants to sleep but Brendan is making a noise or won't leave him alone. Other times Brendan really wants my attention but I am giving Jacob a bottle. You just have to do what you can at the time.
I'm sure it will all just be fine, main thing is to try and stay relaxed.
Just think if you go into labour early like I did you could only have two weeks left!!! :D
Are you feeling ok and managing to get much sleep? xxx