How to attach cable mounting points to a bicycle frame?
I'd go with full housing for both brake and gear cables and hold the cables on with cable clamps. There are many kinds of cable clamps to choose from. I prefer the type that have a screw clamp over the clip on type. The key will be finding clamps for your tubing diameter. 

If you need to have cable stops there are clamp on versions from a variety of vendors. problemsolversbike.com has a variety of solutions for tricky problems.

Items linked are examples and not endorsements.