Not direct equivalents, but assuming you have a variable tfId with the techFile id in, you can do:
leGetContactParam: not really a direct replacement - you can look at the code in this post to see how to mess with the parameters of a via and find the values of a via instance.
leGetContactRule: as above
The problem is that vias are very differently handled in OA compared with CDB (in CDB they were just instances, whereas vias in OA are separate objects, and don't require (for standard vias) a cellView master to represent them).
It might be best to contact customer support so that we can look at your custom code and advise how best to adapt it for IC615?