I thin the Pamela Pro Workout is a great Option. Instead of the Cosmotronic Delta for Envelopes / VCA would you think that the Javelin from WMD or the Sinc Bucina from NE might be also a good choice? Both modules are smaller and it would safe some space.

+1 on pams - personally I like to keep envelopes and vcas separate... more modular - if you want to replace the envelope or the vca you can without replacing the other... also a combined env/vca may be hardwired - so no using hte envelope for something other than the vca and no using the vca with something else to open it... not sure if this applies to whatever - I'd also recommend getting more vcas than you think you need - always useful for cv as well as audio...

AI is a fine choice. Plaits will have more algorithms and cover more sonic territory

Currently I also thinking replacing it with the Manis Iteritas, but I guess that is just preference and both will do great.

both have these have been dsicontinued due to the micro-processor used being discontinued - buy asap to avoid disappointment!

Ghost would be a great all-in-one choice for a small system. It's able to do all these FX at once, plus it has VCA and Filter built in.

I am wondering if I even need a dedicated FX section. My current plan is couple the rack with my Elektron Syntakt and will route the audio from it into the Syntakt. Syntakt has a dedicated FX processor with reverb, delay and sort of overdrive. You can even implement ducking here since my percussion will come from the Syntakt. Moreover, I have some effect pedals for guitar lying around like a Fuzz, Reverb or Flanger. So I could apply FX to the synth voice outside of the rack and give it some more character. Or am I missing something?

guitar pedals are great for modular - best to get a pedal interface module, though - so that the levels and impedence match - there are small inexpensive 2hp ones - AI synthesis for example - and much bigger ones, sometimes with more features, which you may or may not find useful... if your pedals have expression pedal inputs - then the ALM SBG is a good buy as this includes an expression pedal output... the only disadvantage of pedals over modules is that modules are easier to modulate with CV... which may or may not be important to you...

as I stated previously I don't have experience with Elektron devices - but make sure that the inputs can cope with the levels you are inputting... modular is very high and pedals are generally very low...

"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia

Utility modules are the dull polish that makes the shiny modules actually shine!!!

sound sources < sound modifiers < modulation sources < utilities