Honestly i would pick a cheaper highchair, like the space saver ( if you have an extra chair) they are cheaper, and you are more likely to get them, unless your family is rolling in dough.
As for pack and plays, all the "extras" are not needed, seriously. You can get a Graco ( name brand) with a bassinet feature, for about 60-80 dollars, it will do everything the other 150 ones do, but just doesnt have a diaper holder ( not needed) diaper changing station ( not needed) will have a simpler mobile ( again not needed)
I dont reccommend double registering. It throws people off, and they may very well ignore that item completely ( happened on my bridal registry)
There were certain safety things i refused to compromise on ( like my carseat, baby monitor, ect) but things like a highchair or pack and play are not one of them. I would say if some of the things you dont want to compromise on are expensive, then make these a bit less expensive.
Graco Pack 'N Play Playard - Forest Friends On The Go - Graco - Babies "R" Us
this is similar to the one i had, and it was well used. Keep in mind the bassinet features and extras that come with these things only go to 15lbs, so if you have a big baby, or they gain weight quickly some of those extras you paid for will be useless after a couple of months. In the long run, you will only need the bottom portion anyways, all the rest wil be taken off and put away.