Hey IcarusFlyby,
to skip the hand trim router experience is a very wise decision in my opinion.
Congratulations.
Nice how you prepared everything, the things are really waiting for the CNC now! 
Is this the table you plan to mount the Onefinity CNC on? Beautiful stained wood colors.
Assembling cables for VFD and spindle
The ring connectors you bought are not for soldering, they are for crimping. The red color indicates the wire size (red = 22 AWG – 16 AWG) to select the appropriate insert of the crimping tool.
If you solder them instead of crimping, you do not make use of their strain relief.
Hundehalter, CC BY-SA 3.0, via Wikimedia Commons
As you can see in this image, the correct crimping tool has two elements that crimp, the first is to crimp the stranded wire and the second is for the strain relief.
In a stranded wire that is connected to a fixed point with no strain relief and that is subjected to movement, individual strands have a tendency to break, affecting the reliability and safety of the connections.
Your use of heat shrink tube is not really a replacement for a strain relief because it does not clamp the wire to a fixed point.
Also there are a number of reasons why crimping leads to a more reliable connection and why soldering can lead to problems.
One is that when solder is applied with heat, it tends to creep in varying amounts along the individual strands of the wire and the area of the wire affected by the solder loses its flexibility. When such cables are subjected to movement, individual strands break.
Effective crimp connections deform the metal of the connector past its yield point so that the compressed wire causes tension in the surrounding connector, and these forces counter each other to create a high degree of static friction which holds the cable in place. Due to the elastic nature of the metal in crimped connections, they are highly resistant to vibration and thermal shock.
A well-engineered and well-executed crimp is designed to be gas-tight, which prevents oxygen and moisture from reaching the metals (which are often different metals) and causing corrosion.
Because no alloy is used (as in solder) the joint is mechanically stronger.
– Source: Crimp (electrical)
Also the wire you used as you showed with the www link is size AWG 14 (2.08 mm²) but the ring connectors you bought are for AWG 22 - AWG 16 wire (1.31 mm²), which means you bought the wrong size connectors, they are too small for the wire. The correct ring connector color would have been blue, not red.
The colors according to DIN 46245 are:
- Red for wire cross-section area from 0.5 to 1 mm²
- Blue for wire cross-section area from 1.5 to 2.5 mm²
- Yellow für wire cross-section area from 4 to 6 mm²
(For conversion of cross-section area to American Wire Gauge see here:
- Comparison of SWG (red), AWG (blue) and IEC 60228 (black) wire gauge sizes from 0.03 to 200 mm² to scale on a 1 mm grid – in the SVG file, hover over a size to highlight it)
I hope you did not cut or deviate strand ends to fit the wire into the too small openings of the connectors.
I cannot see how you terminated the shield of your spindle cable.
Also, I would suggest not hooking up a VFD and Spindle yourself without checking the very good information in this document:
One thing I don’t understand why you put the spindle cable and the power input cable of the VFD into one sleeve? Usually they go into different directions.