The most reasonable answer is yes, otherwise nobody would be able to participate on this virtual festival. And i think that the old courses still going to be accessible, so you can complete both only to guarantee.
You can start before as long you finish before 31 jan 2025. Usually these vouchers take around 1 month to be received because Databrick's staff is analyzing the results, check your e-mail spam and ads tab because once i lost one 100% voucher because ...
For everyone asking about the retirement of the old courses and the substitution for new ones, of course Databricks is aware that some courses are going to be retired and substituted by new ones. Probably, if you complete the new ones you are eligibl...