If so, do you think both me and my wife need one or would one between us suffice? 

Find an investor that you trust and a handshake should suffice. 

I can't go into how accommodating my bank was .. but suffice it to say they made me many hundreds of thousands in net profit by being there for me

I agree that with a rental a paint job may suffice, but I would qualify that with the type of rental you anticipate.

In order to partner with him he wants me to contribute 1 million to pay off the loan to be a true 50/50 partner on the land so we can develop it.I don't have 1,000,000 in cash lying around so I offered to leverage one of my income producing properties as a lien to the bank which is worth about 1 million.The goal is to roll over his 1 million dollar loan into a 5 million loan which we would share 50/50. 4 million of that would be used to develop the land.He needs my income and assets to qualify for a bigger loan, and I feel like my 1 million of income producing assets would suffice in the form of leverage.The disagreement is that he feels I am not bringing any money to the table in this scenario to make it a true 50/50 partnership.  

Depending on your state requirements a 30 day notice without reason should suffice.

Suffice it to say, your buddy was only stating an obvious fact since bear markets occur on average every 3.5 years.   

The LOC will suffice for proof of funds?

Our contractor argued that we would use a 3" line and that gravel would suffice.

Suffice it to say that you shouldn't believe everything you ready on the internet and you should seek to get advice from people that are insiders in the industry and know what is going on.