How many 240V wires per hole in studs?
You're in the clear, as described

For 310.15(B)(3)(a), this boils down to a very simple rule for circuits 15-30 amps:  No more than four.*   So you're G2G for any of your plans.   You could even run all 4 of these in conduit (as individual wires please...**) 

Also look to see if the instructions allow 2 cooktops on a 30A circuit. 

However... plan for the future

You have the walls open and easy access.  Now is the time for provision for the future.  And this is expensive, high-end stuff, so I don't want to hear about chintzing out :)  Do it right, now. 

Between ranges and ovens, ONE of your cables needs to be ready for 50A w/ neutral -- so a 6/3 cable.  And another of your cables needs be 30A-ready -- so a 10/3 or 10/2 cable; I recommend 10/3 because it makes you more stupid-proof. 

Why? Because that makes you ready for a future installation of more pedestrian fare: either a 50A range+oven, or separate range and oven of 30A each. 

You really don't want to be 10 years down the road, modernizing to a different setup, and discover the only thing in the walls is a bunch of #14. 

Different deal in conduit.  With conduit it is very easy to change wires, so just go ahead and pull #14.  You can easily swap it out for different wires later. 1/2" conduit should suffice. (since you can use #8 for 50A). 





* Why?  First, in split-phase (not 3-phase), all circuits have exactly 2 conductors that matter to the 310.15(B)(3)(a). Four circuits means 8 conductors means a 30% derate.  This derate is off the 90C column for NM-B and UF-B and most other wires.  Separate to that, NEC 240.4(B) already has statutory limits on #14-#10 wires, and those limits amount to 30%-ish derate. off the 90C numbers. 

** And the way you color-code four 240V circuit in conduit is circuit 1: Black x2.... circuit 2: brown x2...  Circuit 3: red x2... Circuit 4: blue x2.  Or whatever. It's perfectly fine for both hots to be the same color.