We agreed on a cash offer, but I'm only able to bring 15k to the table, so I'm banking on my brother or a lender to cover the other 45k within 15 days in cash.My questions are, where do I get a purchase and sale agreement, and how to fill it out, and also how to do a septic inspection before going to title and escrow without getting burned by them backing out and keeping my 7-800 I'll have to shell out. 

Plus they cover a very wide area not just one city or town.

You may be better off charging more rent and covering the pool maintenance yourself, then you know you wont have a green swamp on your hands.

Use the search feature located in the upper right corner of your screen.I also recommend getting a good book covering the general requirements of being a Landlord.

It covers all the counties in California. every county is a little different.New home builders generally charge all closing to buyers, and then give them a credit back for closing costs if they use their preferred lender or some other reason.

We welcome all levels of investors to our meetings and each meeting covers various real estate investing topics. 

Your parents can sign a POA (Power of Attorney) that covers their real estate, or just that one building and then you would have legal right to represent them even in court. 

At a certain point the newer sqft value covers total tear down when completed.

Should I make sure I have enough money saved up to cover me for a few months in the event I'm not able to immediately rent out the property and am stuck with another mortgage payment?

At this moment I will not cover the complete mortgage with the tenant's rent.