No, that won’t work with Prem or Encore very well. You can import .m2TS into PP and Encore, but Encore prefers 720p or 1080p MPEG2 or .h264. And neither program will accept DTS audio. A couple of suggestions

Never let Encore do any transcoding for you. It bloats the files to crazy sizes. Give it everything it wants in the format it requires so that no transcoding is necessary.
If you want to maintain the video and audio quality of the DE, use a temp video and audio track (MPEG2 and AC3), create your menus, then mux your x264 and DTS using multiAVCHD after you’re done with Encore.
To create your temp video, export a 720p MPEG2 at about the same file size as the DE .h264. For your audio, you’ll need an external program to convert DTS to AC3 or WAV (if not too big). I use bigasoft audio converter.

I don’t want to turn this thread into a tech help, so perhaps you could post any further questions in a private message. Good luck!