I think that you probably have the best quality results in the approach that you selected which appears to me as the classical approach.
I do not believe the rest is necessary, but I will mention as a just in case.
You could do a ClipMate Copy/Paste from one project to another if you want to bypass the export route from Premiere Elements. By the way, what version of Premiere Elements are you using and on what computer operating system?
Also, did you ever think about placing the teaser as the first play before the menus for your DVD-VIDEO on DVD disc?
I use PE11 dutch version
PC MEDION® AKOYA® PC P5368 E
Windows 7 home premium 64b
CPU-type Intel Core i7 3770 ram 8GB Geheugentype DDR3 motherboardchipset Intel H61 bus hd SATA-600 Optische Drive Type DVD+/-RW DL Videochip GeForce GTX 560 Opslagcapaciteit 64GB Hardeschijftype Solid State Disk Opslagcap. tweede schijf 1,5TB Hardeschijftype tweede schijf 7200rpm
Teaser has his own menubutton, but don't play auto before movie. But in this case that's not necessary. I don't want people to force them to see the trailer (if you had seen it, you would agree :-) lol )
The reason that I asked about your Premiere Elements version and computer operating system was related to my suggestion of the ClipMate Windows copy/paste between projects. As you can see from the link referenced, ClipMate does work for this purpose when Premiere Elements 11 is involved, but has problem with the copy/paste related to the transitions in the copy/paste.
Thanks for the follow up.