Connector for thermocouple K could end?

I have heating element with integrated thermocouple K, total 8pcs.
For the measurement of temperature used MCU ADC.
To amplify the voltage from the thermocouple 8x zero drift amplifier any as AD8629 (as differential amplifier)
The temperature of the cold end, I will measure any sensor, for example DS18B20.
The problem I have with connectors for cold junction.
Special connectors as they are expensive and difficult to access.
It occurred to me to use the normal terminal , for example this
The question is how big a mistake will bring a solution to the measurement?
Or, how else to solve the problem?

Second question.
I need to connect K thermocouples articles with Miniature Sizes connector
We will advise where to buy cheap female panel connectors for these
any as this

Her is profesional Isothermal Block for Thermocouple Modules with price over 200$ and use standard Terminal block with glued isothermalbar , I thnig bar lead