First off, with an older crowd, even 24 posture may be a stretch. I have had a number of students ages from 14 to 80. It seems that after about 65 or so, unless they are really mentally active, you have to be sure NOT to overload them.

You have it easier if the class is ALL seniors. (Mine is a mix and many times the older ones take a lot of encouragement so they don't quit).

Also, you absolutely MUST know of their physical limitations on a person by person basis. Some modifications are for everyone, some only for one or two people.

Then, I personally never cared much for the new 8 posture and 16 posture forms. They were created for the duan system to build beginner levels. they are precursors to 24. For me, they always seemed too easy. But, for an older crowd, they would be a good tool. They are much less intimidating.

You can get materials on both. If you already know 24, all you really have to learn is the sequence since they are both built from simplifying and shortening 24.

As for Qi Gong...while it is easy to teach a still Qi Gong method...non-moing meditation type or thing or even Post....I would not do that.

Older people tend to have vertigo problems. Standing post can be bad for them with balance. It can also lead to them stiffening up due to arthritis.

I would suggest something like 18 Liangong or 20 Posture Qi Gong. They are moving methods, they work the body a bit, and they can be modified to some extent for people sitting (as in the wheelchair and walker crowd).

Another altrnative is to take 24, remove some of the repetitions, take out the lower snake body, simplify or remove the kicks, and voila! you have your own simplified simplified routine...you can then make sure that everything is done equally on both sides as well.