Congratulations on your new baby!!! Astro is so stunningly handsome!
You did the right thing by not allowing yet for the birds to meet. Aside of the bonding matter, there is also the quarantine - it is a norm whenever you bring a new bird in the house to keep it separated from the rest of the flock/from the other bird just in case there is any illness that isn't showing any signs yet. The time for quarantine is anywhere around 30-45 days.
It is likely that the both birds shout back and forth - it is in their nature! Just make sure strictly not to let them meet, as soon as they see each other they will be persistent in trying to get to the other bird, I had a similar issue with my previous rescue budgie who sadly is no longer here. Rather let it stay like this with a few shouts back and that's it, and lets see how things unravel. It's a good thing you have in mind to first have the bird warm up to you first, and then let him meet Pip, though there is no guarantee if the focus will shift to Pip or not.
And I did have the issue with my conure Pascal where he was ultimately attached to my budgie, to the point we were ignored and feared. And this was more or less solved by separating them in different rooms, I am sure had I done this from the very beginning without having them meet at all, things would've been much smoother for sure... Lesson learned, I guess!