@boon Please note that currently I'm only using the mentioned 433 MHz adapters as simple LoRa devices, not yet with LoRaWAN. I'm also not sure if these adapters are suitable for LoRaWAN (I haven't seen a LoRaWAN implementation using them). I just wanted to experiment a little with Lora devices, investigate their reach (e.g. related to spreading factor and bandwidth).
Regarding the gateways I was mainly reffering to the current gateway implementations which mainly seem to be 868/915 MHz. I think there is nothing that would prevent a gateway from using the 433 MHz band. Also Wienke has promised to supply the gateways according to the locale of the backers. So you should be OK.
Most of the code is identical for all bands, it is just the configuration of the Lora chips that needs some changes. Also the RF hardware part (filters, antenna) needs some adaptions offcourse.