All the 8gb versions will meet the recommended specs for Microsoft Mixed Reality, i5, intel graphics, display port, and the HDD recommendations. Keep in mind these are minimum required specs so experiences will vary based on power.
Nope, there's only front facing camera, but it's not a requirement for mixed reality to my knowledge.
Here are the minimum requirements, got them on VRHeads:
CPU: Intel Mobile Core i5 (e.g. 7200U) Dual-Core with Hyperthreading equivalent
GPU: Integrated Intel® HD Graphics 620 (GT2) equivalent or greater DX12 API Capable GPU
RAM: 8GB+ Dual Channel required for integrated Graphics
HDMI: HDMI 1.4 with 2880x1440 @ 60 Hz HDMI 2.0 or DP 1.3+ with 2880x1440 @ 90 Hz
HDD: 100GB+ SSD (Preferred) / HDD USB: USB 3.0 Type-A or USB 3.1 Type-C Port with DisplayPort Alternate Mode