X3 is still the active issuer. The switchover has not yet happened, which is a good thing, because you can take care of the required changes before you're surprised by breakage. As for new TLSA records, I strongly recommend "2 1 1" (with hashes of the public key) rather than "2 0 1" (hashes of the entire cert). I know that's a change from RFC 7671 (which I co-wrote), but sometimes one learns as one goes along...
Also, you should probably not use DANE-TA(2) with root CAs, they tend to not end up in your certificate chain files (e.g. certbot does not put them there), and some TLS stacks omit self-signed CAs from your chain even if you put them in the chain file. In the mean time DANE requires that DANE-TA(2) trust anchor certs be included in the presented chain. So publish the issuer CAs (R[34] and E[12]) not the roots.