Not too shabby. Although, there's some areas that could be whupped on a bit more...
First up, you might find that a Wasp VCF is a bit too aggressive for ambient. It's also kinda simplistic, which (given ambient's reliance on shifting timbres) could be a drawback. Instead, look at some more complex filters such as Doepfer's A-106-1 (has an insert in the feedback path, allowing you to majorly screw with this via delays, reverbs, etc etc), Limaflo's Motomouth (morphing formant filter), a Rossum Linnaeus (stereo SVF with thru-zero capability), or Intellijel's Morgasmatron (complex dual state-variable, pretty much a "Swiss Army Knife" filter).
As for the VCO situation, I disagree with the above poster. You should look into a VCO setup that has a lot of capability for strange modulation methods, like Intellijel's Rubicon3 or Xaoc's Odessa, plus also consider a simple VCO or two (like Noise Reap's interestingly screwy Bermuda or uBermuda) for AF modulation of either the Cloud Terrarium or whatever second source oscillator you choose. But you DO need more than just the Cloud Terrarium for the sake of sonic complexity/density.
Modulation sources...first of all, that version of Maths is long-discontinued. The 2019 one should be in here unless you have one of these early ones on hand. Batumi + Poti = good. No envelopes (I don't consider the Maths to be just an EG) = bad. A good choice there would be Intellijel's Quadrax, which sort of condenses their Quadra and the Quadra Expander into a single quad function generator. And yes, a Sloths would fit very well here, as might a VERY long EG such as 4ms's PEG.
Things to lose: Links (don't use a mult module in a small build...use inline mults instead), Kinks, and the Ladik mixer. As for the latter two, you need a more comprehensive random source module, with the pinnacle being something like the Verbos Random Sampling (offers many Buchla 265 SoU functions, plus has a shift register for canonic polyphony)...and you need a better mixer that can offer CV over functions such as panning, level, AUX send; the Qu-bit Mixology would be a better fit, and also allow the Erbeverb to be used in a proper AUX send/return fashion.
Now, as for the sequencing...this is where the definition of "ambient" comes into play. Are you trying to do something more determinate and/or "Berlin School"-ish, or do you need something more random or generative and stochastic-based? Or does this need to be more akin to a controller/sequencer, such as a Make Noise Rene/Tempi combo? And whichever one is needed will ALSO determine what ancillary modules are needed to go with it, so it's a bit of a "hole" until/unless you can define how you want that to work compositionally.
Lastly...make the cab bigger. Not that you'll actually wind up with a huge cab, but it helps to be able to create a fully overblown version of what you have in mind first, then pare this back down to something more workable...unless, of course, big is OK.