Basement w/ mushrooms, dirt mound, plant roots & cracked foundation

I'm a FTHB - how concerned should I be? What would it take to address these issues? Should I get a basement and/or foundation specialist to inspect too before my contingency window closes? Help please.

More info:

I'm under contract (with an inspection contingency) on an early 1900 house. Had an inspection done which found a crack in the foundation, visible outside. Unsure how deep it goes. Internally, there's this dirt mound on the same side of the house as the foundation crack. Basement is humid with signs of moisture. There are 2 window openings that are literally open to the outside. Seller has a small dehumidifier that drains into a bucket sump pump & this is clearly not enough to manage the moisture.

Pictures 1-2 external view of foundation crack

Pictures 3-7 are internal views of the side with the foundation crack. There was a previous crack on this wall too that has been repaired, I'm not sure how long ago.

Picture 8 more evidence of moisture (wet spots)

Picture 9-10 are external and internal views of the open window which is on a different wall. Contributing to the humidity I'm sure.

Picture 11 - the small dehumidifier & example of clear view of foundation on other walls

I've never seen dirt like this in a basement, nor mushrooms. Looking at the other walls, I can see the stone foundation & poured concrete walls. The fact that I can't see the foundation on the dirt wall side makes me concerned that I could be missing something bigger. And of course just the fact that this dirt & mushroom growth / plant roots are here is alarming to me. Inspector expressed some concern & said the moisture needs to be addressed but wasn't much more helpful regarding next steps. The report recommends getting a foundation specialist.