USB Audio, not sue exactly what that you had in mind, but most USB audio solutions from $5 to $500+ will work. If you are looking for a specific application/use case, then please elaborate and I will see if I can point you in a better more precise direction:
https://www.amazon.com/s/ref=nb_sb_...field-keywords=USB+audio&tag=tonymacx86com-20
See Also Audio section of the forum:
List of supported wifi -
Broadcom WiFi/Bluetooth [Guide] WiFi and Bluetooth working out of box on macOS with Apple branded Broadcom BCM94360. Enables specific half mini and M.2 BCM94352 on macOS with methods described below. Credit: RehabMan This thread does not support: macOS/Continuity Atheros/Qualcomm...
www.tonymacx86.com
On-board WIFI normally uses M2 or Half Mini depending on the motherboard.
An i7-8700 CPU (processor) has a 'TDP' of 65W - required cooling power of 65W - this is about as powerful as you will be able to use and keep the CPU temperatures from getting to hot, then creating a situation where the CPU throttles down to cool, which reduces performance.
You will not really have space to add an additional graphics card as they are generally bigger than the Streacon FCI Evo case. You might find a single slot Nvidia Quaddro card like the P620 is compatible with High Sierra, although I am not sure that it will fit in your chosen case. Harder to ascertain if this is supported in Mojave though.
The NVIDIA Quadro P620 combines a 512 CUDA core Pascal GPU, large on-board memory and advanced display technologies to deliver amazing performance for a range of professional workflows. 2 GB of ultrafast GPU memory enables the creation of complex 2D and 3D models and a flexible single-slot...
www.pny.com
www.tonymacx86.com
FYI
The single slot XFX RX 460 shown in the guide below You linked above) is not macOS compatible:
Streacom F1C Evo WS buid... with an RX 460. If you avoid looking too closely at the custom IO, PCI slot, DC in, GPU intake and GPU bracket, it actually looks alright. Specs: g4560 128g 600p M.2 SSD picopsu 160XT XFX RX 460 Slim 4g The first iteration of the build used the case fan as an...
smallformfactor.net
For running a system from battery powers - I do not know of a laptop battery type of power supply. Remember that a lpatop CPU will consume ~ 5W -30W at most. A desktop i7 processor is far more power hungry and this will be the achilles heel of portability. You may well be able to build something for your needs with this regard, but I am not aware of it being done on this forum in the past.
The following is an up to date mini ITX build that would fit inside your Streacom case and has WIFI, updated cooler for quieter running and more efficient cooling (given such a tiny case). A modest 160W Pico PSU with external laptop power supply are linked:
erik's "Tiny But Mighty" High Sierra Coffee Lake Build: i5-8400- Asrock Z370m-ITX/AC - Intel UHD 630 - 16GB RAM https://i.imgur.com/36H9GAd.jpghttps://i.imgur.com/DWLV1yp.jpg?1https://i.imgur.com/lIetM5x.jpg?1 Components Intel Core i5-8400 Coffee Lake 6-Core 2.8 GHz (4.0 GHz Turbo)...
www.tonymacx86.com
Not every mini ITX motherboard is fitted into such a small case - you will find users that have adopted larger cases, full size graphics cards, Big CPU cooling solutions and have used a wide range of hardware. if you find builds that use a mini ITX motherboard, then you know that someone else has used it successfuly.
www.tonymacx86.com
I am sure that you can find a suitable SATA slot load DVD drive