Maybe keep them separated for a night or so-they'll smell each other and play it by ear,being young they should be fine but i would say slowly, slowly some are quicker than others and they've had some big changes already in a small amount of time
Also 1 cat/kitt is just as much as having 2-not much difference and twice as many cuddles and fun ti be had
I'm sure you and they will get along just fine-and please do try and post pics of your cuddle muffins