After all, I"m sure you can copyright the actual material but not the process of finding properties, lol. 

Time, money, materials, contractors.

Electrical connections get loose and wonky, roofing material flies off, gutters get tore up, hvac and water lines get messed up. 

Choosing the most expensive insulation because it's the most energy efficient, should allow you to reduce and/or eliminate costs in other areas.4 - Energy efficiency isn't made up of added costs.5 - Energy efficiency is the product of reducing energy needs, not supplying added energy.6 - Cost effectiveness is a product of maximum use of materials, as in little or no waste.All of the above should be obvious, in parts. 

If actual costs are higher then projected costs ( rise in material or labor cost), the GC may come back and ask for more money. 

@Jonathan Roper Can we just import those workers for time and materials for a few weeks?

They will often want a new building constructed and building today with labor and materials is very expensive versus retrofitting existing building.When I buy value add vacant buildings the goal is to double the return on investment within a 3 year period.So if I can use the existing building and retrofit to same concept ( example previous burger inc. but now Whataburger wants to come in ) then not as much tenant improvements to convert.So if rent 20 a foot for 5,000 ft that is 100k NOI NNN a year. 7 cap value is about a 1,400,000 stabilized valueSo if I buy it for 400k and have 300k in it more 700k to get new tenant in the value is then around 1,400,000 based on NNN 20 a foot and a 7 cap rate exit value.If you want a premium price then you would need to sell to an end user tenant ( regional or national in nature) that wants to buy the building and put their concept in there.

I have seen before 1031 buyers lock in 3 choices but not get some material while under LOI to see if property is viable for cash flow returns and for financing they would like.

But I’m thinking in order to use passive losses from other entities (multi family, SFR’s, etc) I would also have to show material participation in those activities in addition to the REPS, is that accurate?  

Metal buildings will be easiest and most cost effective but you need to research your market to make sure you build the right configuration for the potential use and prospective tenant.