Need expert advice! How scary are foundation issues?

[Meghan Letters]

Hello Bigger Pockets community!  

I'm a newbie working on getting into my first flip. I'm super green so wanted to put this out to this wonderful world of experts I've been reading here at BP.  Reports just came back on this house we are offering on and some of the pest report showed issues with the foundation. Things like fungus damage of the subfloor, support posts in the crawlspace in soil contact, hairline cracks, and (scariest to me) no foundation on a portion of the structure though majority is pier and block.  Am I crazy to continue with negotiations? The property was built in 1900, has a ton of charm and in a historic neighborhood.  The numbers work for me considering a reasonable amount of work to do but the possibility of these kind of projects being a Pandora's box situation seems high.  Am I wrong? 

Any advise, experience or words of wisdom is appreciated!!  

Thank you!!