How do I buy CHA?
During the burn period, all you need to do is send BTC to 1ChancecoinXXXXXXXXXXXXXXXXXZELUFD. You can do this using Bitcoin wallet software, or using the standard Chancecoin wallet or command line interface.
(my emphasis added above)
For the moment, let's set aside any question of whether this is a gimmick or a scam. You seem to be modeling your proof-of-burn after Counterparty. However, if I recall correctly, Counterparty had some very specific formatting requirements for their burns to be successfully picked up and recognized by the Counterparty reference client and "converted" to XCP. You couldn't just send bitcoins to the burn address from any client -- initially you needed to do it using the Counterparty software, and then later some very specific (but tricky) methods were also rolled out, such as a blockchain.info method.
So...at a technical level, how exactly will someone be able to obtain CHA by simply sending BTC to your burn address by simply "using Bitcoin wallet software"? Is that really all that is required? Or is the protocol actually more rigid (as it was with Counterparty), and do individuals casually sending BTC to your burn address risk losing their hard-earned BTC if they fail to meet that protocol's format requirements?
As of now, you can burn BTC into CHA using any Bitcoin wallet software by sending BTC to the burn address. The input must come from a single Bitcoin address. There can be multiple output addresses in any order, as long as one of them is the burn address (1ChancecoinXXXXXXXXXXXXXXXXXZELUFD).