Leaving aside the scanning aspects, I like Portra 160NC.
Mixed lighting is asking for headaches (and if you think you can fix it in post, that's even more headaches), if you're in a controlled situation and don't need to shoot with mixed lighting, and if as you say you're new to this kind of photography.
First you've got the issue of balancing flash and ambient light levels--aperture and/or power setting on the flash will control the flash level, and shutter speed will control the ambient level. You can think of whichever is greater as the main light and whichever is less as the fill light. A meter that reads ambient and flash makes this much easier. The alternative is a lot of testing and note taking, from which you'll learn quite a bit.
Then you've got to match the colors of the lighting sources, and ideally gel the flash to the same color as the ambient, and then you might need a filter on the lens to match them to the film. If you've got three or more colors of light, it gets more complicated. You can use a color temperature meter, but it's expensive, particularly if it reads flash. You can also approximate based on generally accepted values for flash and tungsten, and if there are fluorescents in the mix, you can look most of them up in tables. You can also test, but if you want to see how the specific film responds to the light, this takes time, and if the exposure time is particularly long, there may be reciprocity related color shifts.
Do you need an aspirin yet?
Better to go with the available light to start with, if it's all of the same type and you feel you can use it in an interesting way, or use strobes with modeling lights so you can concentrate on the main issue of how to light the subject without worrying about the fussy details of mixed lighting.