Here are the answers to your questions.
Q1: Will providers be able to manually submit their QPP data for all categories using their EDIM account?
A1: Yes
Q2: Will providers have the option to upload a QRDA III file?
A2: Yes
Q3: Will there be an option to upload a JSON file (in QPP format) too?
A3: Yes
Q4: The QRDA III file could include data for all 3 categories as a single file based on the 2017 specs?
A4: Yes
Q5: Does it have to include all the 3 categories or can it be for one or two categories too?
A5: It can be one or more categories.
Q6: The QRDA III file could include data for a single provider or for the group?
A6: Yes
Q7: The QRDA III file can only contain data for the eCQMs. The eCQMs version ids have to match the ones in measures.json file.
A7: Yes
Q8: For obvious reason, the QRDA III can not be used to submit registry measures. Providers will need to use a registry to submit any registry measures.
A8: Yes
Q9: Can providers use registry to submit the quality data and manually upload ACI and IA data?
A9: Yes
Q10: Our understanding from discussion with QPP support is that there is no separate " EHR certification" to create these new QRDA III files for all categories. By submitting the data, the providers are attesting to the 2 facts below: