I am definitely not an expert and only may partly answer some of your questions mostly regarding the using of blu-ray files and that are already compliant with blu-ray specs.
My little knowledge of high def. cameras...I can only say it appears to me the makers of those cameras made sure they made it difficult to get it onto blu-ray without jumping through the hoops.
At minimum, you will need a blu-ray player to playback either blu-ray discs or AVCHD discs.
If you wanted to bypass making discs, there may be some hardware media players that would play the files to your tv, perhaps straight from camera (not really sure about this, you could research it and see what info you find).
You can make AVCHD disc with a DVD burner and then play it back on a blu-ray player, at least that is what I have read.
An AVCHD disc amounts to putting high def. on a DVD disc.
If you want to get a blu-ray burner, prices aren't too bad on them and like mentioned the disc can be had from about a $1 to $2 each.
The very best software for writing to discs, whether dvd or blu-ray is
IMGBURN.
I usually use the write speed of 4X for writing to blu-ray with very good results.
Getting your source compliant will be the first hurdle, there are sites that have that info about compliant BD files.
When your file is compliant, there are several choices of both freeware and payware that
can take a blu-ray file and convert it to dvd format.
3 right off the top of my head are Multiavchd, BD Rebuilder and
ConvertXtoDVD.
The first 2 are freeware...Multiavchd is buggy but the only freeware available that can actually author a (menu-ed) blu-ray file ready for burning to disc.
BD Rebuilder can re-encode a dual layer Blu-ray to single layer or take a blu-ray and convert it to dvd with very good quality. It can also take some other input formats and output to some different formats.
ConvertXtoDVD can convert a blu-ray disc file to DVD but the quality isn't quite as good as BD Rebuilder but it can convert the file a lot quicker.
Both Multiavchd and BD Rebuilder can make AVCHD files.
I don't know if any of these can deal with the non-compliant blu-ray file from your camera though, you could try them and see what happens I suppose.
If it were me....I tend to do the least I can to get the job done so...I would see if a media player could play the file straight out of the camera.
You could hook in your computer to the TV....or see if there are any hardware media players that will play the file without having to manipulate it any.
If you take the route of trying to get it blu-ray compliant, I would be curious what program(s) would get this done.
Perhaps others here have dealt with this and give some good advice.
Oh, I see you were wanting dvd for others....still getting the camera file compliant likely would be the first thing to do.