hmmmm.... I think you'd be much better off with a bigger case and something like a keystep pro... because you wiull need the expansion space almost immediately with this setup... I'd really suggest a great deal more research before parting with cash....
there are fundamental things missing...
your description of the intellijel adsr's compactness made me chuckle... as did the "you can never have too many lfos" when there's only 1 in there - the "you can never have too many.." meme is usually used for vcas...
speaking of which, there are no vcas to plug the envelope generator into... ok there's one on the tonestar, but that already has an adsr built in...
buchla is often linked with lpgs (not filters) which are also none existant... these are a cross between vcas and low pass filters...
whilst the tonestar is a voice - the tiptop/buchla module is a dual vco - you will see on the tonestar that the vco is a small part of the voice... they have no
reverb and delay are both incredibly useful...
take a look at my signature and think long & hard about how you might apply this to a rack that you might want...
seriously consider a minimum viable synth (at least to start):
a sound source (possibly rthe tiptop buchla one), a sound modifier (possibly 1 of the filters), a modulation source (you'll want more than 1 channel - a quad is a good idea, batumi - or possibly maths - particularly if you are into west coast serge/buchlaesque concepts), a way to listen (a quad cascading vca will work wonders as a basic mono output - a veils clone) and a way to play (maybe a keystep pro - or a pams - which could also double as a modulation source and a random pitch source) and a basic utility module for attenuation/inversion/offset (happy nerding 3 * mia)
another good idea is to work out what modules you want (based around how many voices you want) what modules each voice will need, what supporting modules they will need when combined and then work out how much rack space you need - leaving a good 25% of any rack you buy free for expansion - you will need it... instead of deciding on a case because it appears to be convenient...
if you want to fit the 4 voices that the nifty keys is designed for you, into it, you need to go much more compact with every module...
"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