Can you have an ABR without a connection into Area 0? How can this be done and would it be wise? Thanks in advance.
No, that is not possible. An ABR is a border between area 0 (the backbone) and another non-zero area.
If you have a router with two non-zero areas on it and no area 0 backbone, the areas will not talk to each other. (But the area 0 can be a virtual-link if you want.)