Here is a comparison of specifications for the cameras you listed:

http://www.dpreview.com/reviews/compare_post.asp?method=sidebyside&cameras=canon_a3100is%2Ccanon_sd780is%2Cnikon_cps570%2Cnikon_cps3000%2Cpanasonic_dmcfp8%2Cpanasonic_dmcfs25%2Csamsung_st550&show=all

I think any of those cameras would produce equal portraits.
None has any particular advantage.

But as far as excellent; that is in the hands of the photographer more than the camera.

Indoor portraits are a problem because of lighting.
Flash photos are not recommended for portraits, because the lighting is usually too harsh.
That means you really should be using flood lights.
If you positioned the person near a window, you could do well with natural light through the window.
To do this you will need to use a tripod because you will be using a slower shutter speed.

Since you should shoot portraits at 50mm to 100mm focal lengths, you will need to set the cameras you listed at about 3X optical zoom for your portraits.
Shooting at 3X means the lens aperture on any of those cameras will be approximately f/5.5
That means you must be careful about what is behind the person, because it will be clearly seen. The use of a colored sheet as a backdrop could work well.

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