Don't know the risk of doing any major renovations within that time,mcreating some "equity" above the auction sale price.

To my knowledge , nowhere in the rule book does it say that your profit needs to be made available to seller .

I narrowed it down to my major strategy/criteria.

A lot depends on your risk tolerance, projects you do in a year, profit margin and any plans you have for yourself in the future.

Don't ever offer anyone a portion of the sales price of your property - offer a portion of the profits... that way the investor assumes some of the risk in return for more of the profits, but you aren't locked in to paying them a certain amount if you have to drop the price and get out of a bad deal

Their profit would be taxed further reducing the flippers take home compensation. 

@Sharath Kumar the pop corn ceilings could be a major problem along with any texture on the walls if they are asbestos or lead containing. there is no way to do it your self in Colorado both the removal of asbestos and lead are highly regulated by the Colorado dept of public health's air pollution division, it would be really dangerous to attempt to do this type of friable removal in an apt building because of the shared air systems used in the 1970's you could  contaminate the entire building with asbestos fibers or lead dust.

But the majority of them said to wait it out. 

As a result profit margins are very thin here.  

Yes you will most likely be splitting profits but after a flip or two you will have the necessary funds to revisit the funding options you mentioned above.