I've been running multiple student rentals for years in Reno, NV and it's been a very similar experience. 

While I do not personally have a contact in KC, I'd recommend using BiggerPockets' Find an Agent tool.Its a FREE service for BP members like yourself who are looking to expand your network and find local experts.Here, you'll be connected with an investor-friendly with knowledge/experience in your desired location(s). 

Your unfortunate experience is summed up in the word ‘trust’.

Finding the right team to assist you in your journey is what is most important, that way you have guidance, experience, and a partner that is looking out for your success in your investment. 

Could you please share your experience of how you go through these obstacles and how do you choose your state and properties to invest in (if you are investing in tax deeds as well)? 

As far as down payment, investment properties typically require a minimum of 20-25% depending on property type, FICO, level of experience, occupancy %, etc.

I am hearing you when you say you had the builder fix the grading issue, but grading is in my experience the #1 cause of repeated water in the basement.

Initial budget $250-600k +- Please advice if it's seems like an ok plan in your opinion (preferably if you have personal experience). 

This will give you some hands-on experience and an opportunity to put into practice what you have learned from reading the book.

Hard Rock Hotel (Downtown San Diego) has offered investment ownership opportunities for certain rooms within their establishment... has anybody had experience with this or horror stories of such investments?