esp32 has both bluetooth and wifi. It doesn't matter if the module name is "ttgo" or something else, if it uses "ESP32" it will have BT and WiFi 2.4
(Keep in mind that ESP32 != ESP32S2, they are completely different chips with different capabilities)
Yes in theory you can. How hard will be depends on dslr brand and model, if someone has reverse engineered the protocol, if there is any library etc...