So if the waste gate solenoid is unplugged and the waste gate is working only off its spring, will the second turbo still kick in since the spring on the waste gate is about 7lbs ?

By this in the trouble shooting the second turbo it says this:

Note that the Primary Turbo must be operating and generating more than 7 psi of boost to be useful for any of the solenoids or actuators to work for the secondary turbo.

 

Yes if you unplug your precontrol/wastegate solenoids, your boost pattern will be 7-5-7.