I haven't tried what you're trying to do with an 8nu8r.
The A-119 does have an envelope out and a gate, as well as audio out.
If money is an issue the minimum setup I would recommend is 1/4" input and output modules, the Wasp Filter and an Erica Synths Pico DSP and a few VCA's. Next I'd get an Envelope generator and LFO to see how they effect the sound. You may want distortion or a different filter. I like the Erica Synths Dual drive for distortion. Basically refine the sound you're getting to the amp.
It's likely going to take a bit of experimenting to get through this process.
The Morphagene and Clouds are useless if you don't have sounds you like. I wouldn't get them until you get sounds you like going to your amp.
Also, search Google and YouTube for "Guitar through Eurorack" to see what other people are doing.
Good Luck!
Burousu