Improved Familiar Level Requirement

[Greenkiper]

I am playing a campaign as a sorcerer and we have encountered a ratling that really wants to be taken as a familiar. I am currently a level 6 sorcerer. As I do not have access to a familiar from my bloodline, I was going to take a level of wizard at level 7. It would give me access to a familiar, a feat to take improved familiar, and the requisite seven levels to be able to take a ratling specifically. However when I do so, I get a validation error that I must be level 7 to take that familiar. I am trying to figure out how to adjust it so that the familiar adds properly. I tested with a level 8 character, 7sorc/1wiz, and got the same error.

So questions:
Do I have to be level 7 with the class that gives the familiar in order to get the improved familiar?
Is there any way to do an adjustment in hero lab to remove the level requirement needed to take a ratling for a familiar?

Thank you