Hello and welcome to FF ! Think when you mentioned the different pets you and girlfriend want; forum members presumed you were planing to mix them. Just in case; that is a no no.

Best thing to get you started is to head to the Vivarium Section and read some of the excellent build posts in there. Recommend look at those by Bill (Deranged Chipmunk); specially this one: http://www.frogforum.net/vivarium-te...aludarium.html.

The issue with water is that in vivariums; it tends to go where it wants to without exactly following the builder's intention. Your substrate (ABG type soil for the plants) need to remain above the water level and not flooded by water features gone rampant. If it get's soaked, substrate will become a bacteria breeding bog. In the case of your desire to build a 360 degree observation peninsula type display; those planned water features are going to be challenging to build since there is no background in which to hide the equipment (pump and or filters) and tubing. And everything has to be sealed tight with no way for a frog to access the equipment area.

P. bicolor are outgoing frogs. We do not have a care guide for them yet; but you can use this one to get an idea of it's requirements: Frog Forum - Care & Breeding of the Golden Poison Frog, Phyllobates terribilis. Good luck !