Q: Can't Find a update or latest Version of iDVD to Download or a Compatibility to Yosemite

As long as you can get a video DVD authoring app that can save the project as a disk image you can use Disk Utility to burn it to disk. 

I suggest you download and try a couple of the free authoring apps from the App Store.  That will show you what's available.  There are some that also offers a "pro" version with more feature and for a price of course.

I tried "DVD styler" (older version newest quits with error), but after importing the mpeg2-PS file created by Avidemux it began to show a progress bar that holds still at 7/206 minutes, 3MB/s. Dont know what to think of it. It is not quiet intuitive.

This didn't solve it http://avidemux.org/smif/index.php?topic=3570.0

I guess I will observe Ebay and when a cheap copy of Toast 11 comes along I'll get it. today I missed one, that sold for 13,-EUR. I also plan on getting iLife 09 somewhen. So for the future I will have those as a more recent app and a fallback option, until I find out, what to do with the mpeg2-PS file.

I wonder though anyway, why it is a PS file, when the folders on a DVD are usually TS_folders. (but PS is what is preselected, when hitting "auto->DVD" in Avidemux).

I now found out you can drop a mpeg2-PS file produced with Avidemux on an App called DVDStyler and it will create a DVD for standalone players without re-encoding.

But! Only version 2.5 and 2.4.2 (which might have very old ffmpeg encoders, version 2.5.2 states ffmpeg 1.2 and DVDStyler 2.3 states "added support for libav 0.9 / ffmpeg 0.11 and chenged to use avconv tool to transcode.", no one knows what version might have been used up to 2.5 and from 2.4 on.)

I got highly criticised by a Windows person on another forum, for saying it doesn't work (the developer stated it worked under 10.9 but had coded it under 10.10 recently, he didn't answer what the older versions, e.g. 2.6 from 2013 were coded on). The fact that it has very low download times on soruceforge for the Mac version and this app has never crossed my way before on Mac Forums, makes me believe it is either not spread very much or it failed for other people, too, and they reported in Mac forums and the App got forgotten, because it was said to never work).

2.5 however (while not stating a re-encode) produces a 2400kbps file out of a ca. 2550kbps file, while 2.4.2 does create a file of the same file size as the soruce.

Just one more question, one user mentioned, that he got iDVD 7.0.3 with iLife 09, but found an Update to 7.0.4 on the apple page iDVD 7.0.4 and after that he could update to 7.1.2.

iLife 08 comes with 7.0.0, if I am correct. Would it be possible to update 7.0.0 to 7.0.4 and then 7.1.2?

For those who wonder, wikipedia says although 7.1.2 is from 2010 (or 2011?) ist doesn't add a better encoder. 7.1.2 is still 7.0 from 2008 and just fixes some minor bugs.

iLife 08 comes with 7.0.0, if I am correct. Would it be possible to update 7.0.0 to 7.0.4 and then 7.1.2?

Yes. As long as you have some version of iDVD 7 you can get to 7.1.2 via the updaters.

This is not correct.  I installed iLife 09's iDVD 7.0.3 from disk and now it will not allow me to update to 7.1.2.  It tells me I must have 7.0.4 or later to perform the update.  I also found a copy of 7.1.1 off the Apple site and it wouldn't work either with the same message.  ANyone know where I can find the 7.0.4 update?

Thanks!

Well, of course, if you change the search terms in Google, it'll come up...  Sorry.  Here's the link to iDVD 7.0.4 update:

https://support.apple.com/kb/dl843?locale=en_US