Crude CAD of a pancake bay similar to what I have in my (unfinished) Tembo. I don't really know the dimensions of the Telemini or the EF Mini but here is an idea of how you could do it. Wiring may be a nightmare but it can be done.
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Blue cylinder is the Loki motor.
Orange CR on bottom holds two charge wells and an attachment point.
Next forward is a bulkhead set 1/4" above the motor. It holds 3 LiPo batteries.
Next is a bulkplate that holds the Quark and Telemini, the green blocks. A notch is cut in this BP allowing the EFmini to pass through. The long purple block is the EFmini setting on sled, the teal piece. The other teal piece between the altimeters is just a support for the EFMini. Probably not necessary depending on how you mount the EFMini.
Top plate holds two charge wells and a penetration for the EFMini antenna, which can be protected using a small tube.
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Another view. The bottom ring and top plate should probably be stepped just like a regular lid. The blue tube is a piece of MMT glued to the CR and capped to seal the bay. It could actually be glued to the green plate holding the batteries.
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The electronics payload.
Like I say, don't have details on Telemini.
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The batteries.
The batteries I used for a measurement are some I got off Amazon. 300 MAH, 2S LiPo.
Another option to be to mount the batteries to the green plate or the bottom CR, but radially around the motor. They may get a bit hot doing it that way though.
The screw switches could be mounted anywhere in the switch band.
The green and red plates don't need to seal anything so they can be drilled, notched, or whatever to allow cable routing and, in the case of the green plate, to assist in mounting the screw switches.
Of course you will have to place your all thread or whatever you use. But that shouldn't be too difficult either.
I have standoffs separating my plates and all thread holding it all together. Assembly takes some time but that is just the nature of the beast.
You could always forego the all thread and use rod couplers epoxied or fiberglassed to the inside of the coupler.
Yes I know the drawings are pretty crude and the nose cone isn't an ogive, but maybe it will help give you some ideas.