How to get panorama using few photos warped properly?

These "bends" might be from distortions from your camera's lens, which Hugin will have a hard time correcting for, if you supply only a limited number of pictures. Check the lens distortion parameters in Hugin for your panoramas (a,b,c - barrel, pincushion, wavy).

You can apply the lens distortion correction in Lightroom, UFRaw, similar tools or Hugin itself first, then use Hugin to stitch. In my experience, this gives better results with known lenses and only a few pictures in the panorama.

If memory serves me you can force Hugin to make certain points form a horizontal or vertical line in the final image. You might look into that. Note however that forcing one part of the image to adopt a particular geometry will typically result in other parts of the image being distorted.

Manually selecting matching point and lines can also help, but again may result in you forcing an image into an unrealistic mapping that will have other distortions.

However the way you get a good panorama is to use a large number of heavily overlapping shots. So you already know the correct solution to your problem.

Trying to wing it on a small number of images is exactly the problem. Hugin (and any other software) will have a very hard time without enough overlap to figure out a decent mapping without enough information. I'd normally aim for 50% overlap horizontally and 50% vertically if I'm doing a vertical pano as well.

Don't know how this would apply to using multiple cameras for video, but these types of stitching errors tend to occur with parallax or camera movement in space between member shots. Parallax is more easily corrected in stitching with more overlap, but when you've got less, there's not much you can do. With stills, you need to determine the no-parallax point of your lens and be careful to rotate around that, which is why panoheads, like the Nodal Ninja, exist. Camera movement, you may need specialized stitching software (e.g., PTGui's viewpoint correction).

I would recommend that you consider remapping images from fisheye lenses (where you can often get 140-150º HFoV), or maybe consider a 360º camera, like a Ricoh Theta or GoPro MAX.

See also:

• How are virtual tour photos taken?
• What are the best techniques to take 360° panoramas?