Engineer Inc PA-20 Precise Universal Wire Terminal Crimping Tool
These are what I use almost daily.

Engineer PA-21 Universal Crimping Pliers
These are similar to the PA-20 but much better for JST VH connectors.

Engineers Precision Crimping Pliers Pa-09
These are good for the smaller connectors and much better than the IWISS IWS-2820 tool linked below but cost a little more than double.

IWISS IWS-2820 Mini Micro Open Barrel Crimping Tool
Not the greatest but probably good enough for occasional use. The three pairs I have of these all have some difference in quality but for the price I didn't expect much.

IWISS SN-2549 Crimping Tool
This was my first crimping tool for wire-to-board type connectors before I knew any better. They crimp both the wire and the insulation at the same time but in my opinion are more of a pain to use than the other tools that you first crimp the wire then the insulation.

Klein Tools 1019 Klein Kurve Wire Stripper / Crimper / Cutter
My most used and preferred wire stripping tool. I thought the Irwin tool below was great but I think that was because in the past I always had used cheap tools. I was hesitant to try this pair due to my past experiences with lower quality tools of this style. I rarely use the Irwin tool anymore.

IRWIN VISE-GRIP 2078300 Self-Adjusting Wire Stripper, 8"
These work okay but I prefer the Klein Tools 1019. I find these don't work too well when you only to remove two or three millimeters.

Hakko CHP-170 Micro Cutter
These are good for cutting 16 gauge wire and smaller. Work well for trimming component leads. These have lasted longer than some of the other wire cutters of similar type which have likely been low quality clones and this pair is doesn't cost much more. Another use is trimming small pieces of plastic from printed models but be sure not to cut anything too thick else risk one of the jaws breaking off.

The rest of the page below this line is not complete. Needs a little more detail and organization.

Heater plugs housings are JST VHR-2N series - Digi-Key.com

Power input plug housings are JST VHR-3N - Digi-Key.com

Pins for the above plug - Amazon.com

All other plugs on the V1 mainboard except heaters and power are JST XHP series - Amazon.com

Look around before purchasing. Those above links are just meant to show the size/type you are looking for.

You can 24 or 26 gauge wire for the thermistor or if using a prewired thermistor just use that.
Use silicone jacketed high capacity stranded wire. It is made to be flexible and heat resistant.

JST PHR-6
6 Position Rectangular Housing Connector Receptacle Natural 0.079“ (2.00mm)

Digi-Key.com - PHR-6: 6 Position Rectangular Housing Connector Receptacle Natural 0.079" (2.00mm) - Digi-Key Part Number 455-1162-ND

Amazon.com - Search for "JST-PH 6 pin"

Amazon.com - Search for "JST PH 6 pin"

JST Sales America Inc. SVH-21T-P1.1
Description: CONN TERM CRIMP VH/NV 18-22AWG
Expanded Description: Contact Crimp Socket 18-22 AWG Tin
Wire Gauge: 18-22 AWG
Manufacturer Part Number: SVH-21T-P1.1
Digi-Key Part Number: 455-1133-1-ND
VH Series Datasheet
VH Series Online Catalog

JST SVH Crimp Terminal, Female, 0.33mm² to 0.83mm², 22AWG to 18AWG, Tin Plating
RS Stock No.: 762-0702
Brand:JST Mfr.
Manufacturer Part No.: SVH-21T-P1.1
Product Details These VH Series of Wire to Board, 3.96 mm pitch, Through Hole Connectors from JST are suitable for use in a signal, power supply or output circuit applications. The compact size and large capacity coupled with secure contact and mounting are the special features of these VH Series of Wire to Board, 3.96 mm pitch, Through Hole Connectors.

JST Sales America Inc. VHR-2N
Description: CONN HOUSING VH 2POS 3.96MM WHT
Expanded Description: 2 Position Rectangular Housing Connector Receptacle Natural 0.156” (3.96mm)
Manufacturer Part Number: VHR-2N
Digi-Key Part Number: 455-1183-ND
VH Series Datasheet
VH Series Online Catalog