El Capitan & Photoshop CS4 / Illustrator CS4 / Excel 2008

there is no guarantee from anyone it will work and if you find it doesn't work for you no one is going to fix it, ever.

in order to maximize the possibility it will work I suggest a clean install with nothing that can be present to interfere.

to do this follow these steps:

back up your computer with Time Machine

do a clean install of OS 10.11.3

from your administrative account install CS4 and run photoshop

install JAVA 2015 for Mac

https://support.apple.com/kb/dl1572?locale=en_US

update CS through photoshop.

restore your previous data from Time Machine for remaining data.

Excel 2008 is not officially supported either but some reports show it works in 10.11

again I would follow the same install procedure as CS4 with a clean build of the OS to minimize potential 3rd party incompatibility or corruptions.

Fetch 5.7.5 work, I'm using it now

CCC may require an update

https://bombich.com

Acrobat 9 is 8 years old no longer supported, Adobe states it is no longer patched against PDF based attacks and you should upgrade. The current version is Acrobat DC. Again if you find issues no one from Adobe or Apple will intentionally fix it.

graphic converter has a test download you can try before you buy

http://www.lemkesoft.de/en/products/graphicconverter/download/

your remaining 3rd party software will need to be checked from the developers website as to if they have 10.11 stable versions, if your versions are eligible for update, etc.

I'm running Photoshop CS3 with El Capitan and it runs very well. However, after upgrading to EC you will need to download and install Download Java for OS X 2015-001 for PS to run.

I'm also running MS Offie 2008. The only issue is that the apps can't interface with the new Photos library. If you need to insert an image from a Photos library the image will have to be exported to the Desktop and inserted into the document from there.

You'll need to update Fantastical to 1.3.18. There are also updates for GraphicConverter, CarbonCopyCloner that work with EC. Can't comment on the others.

If you want to continue to use iPhoto with EC be sure to upgrade to iPhoto 9.5.1 via the App Store before upgrading. You can then upgrade after EC to iPhoto 9.6.1 which runs with EC.

I did a regular upgrade to EC and had no problems with the apps. A clean install is not necessary unless you're having problem with Yosemite. Be sure you are up to date with all of the MS Office 2008 updaters.

FWIW, I run GraphicConverter 9 (9.7.5) and iPhoto 9.6.1 without any problems.