And there's not really a chart of what qualifies for shorter depreciation, it's more like "assets used in distributive trades and professional services, not including section 1250 assets." are 5 year assets.

Currently, I am exploring in CA: Oakland, Pacifica, Sacramento, Vallejo; UT, TX.

These are professionals with additional training and a stricter code of ethics.

when I say you lose money its all the money you pay 3rd party professionals to do proper due diligence you get your EM Back.in the case of my situation right now were I have just under 400k in cash out on my Oregon deal.. if I don't close I lose it all.. but this project also will make us almost 10 million over 3 years.. so like I said RISK/REWARD... and when you step up to big land deals your competing against big players.. like my deal I just beat Lennar and Horton to it..

Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

Professional tenants.

Your worries will be alleviated by using another professional.  

Your tax professional will lament about paying $2000 in taxes one year v $200/yr over 10 years (it's the same damn number), but we're talking about two hundred grand, so this shouldn't be a hard choice. 

I'm wondering what is the best and most professional way in approach another investor to try and convince them to let me be apart of their deal/project?

It may not affect a single deal, but if you get a reputation in your area as someone who isn't reasonable, is always trying to save another $1000, then you run the risk of other professionals calling your competitors instead of you when deals come up.Being easy to deal with and understanding that the other guys need to make a buck too goes a long way.