If the objective of those people who want to learn about investing is to create wealth over a long period then that's how you should structure your talks/exercises. If the objective is quick and flashy returns then teach them how to trade - and warn them that at least 70% of all traders fail.
Most of the transactions are conducted over the JSE read up on their offerings, Simon Brown runs his Power Hour in Joburg, Durban and Cape Town plus there are webinars, he also has a website Just One Lap - use what's out there don't reinvent the wheel. Some of the Banks run client/sponsor interactive sessions - get invites to these.
The important issue with investing directly on the stock exchange is read as much as possible, many will advocate Benjamin Graham as an almost set book - I found it boring to the nth degree
If you want to teach people how to invest then be honest, by which I mean relate you own good and bad experiences, after all investing in the exchange is all about how you learnt yourself, how you got your fingers burnt and what your winners were/are.
On the question of investing for other parties in your own name - make sure that these trusting people can get their money back i.e. insure against losses and ensure your will reflects that you owe sums of money/shares to individuals
