Any QI with demonstrated experience and a national foot print will be able to help you out. 

Would a more environmental approach to a new build/flip be more costly so developers and flippers sway away from this?

DWQ, Army Corp or any other environmental requirements or permits.

roof is over the attic which has the loose insulation, wind, environmental hazard) and also looking to put in can lights in the kitchen.  

Are there any environmental issues?

Don't go too dark because it will show up every footprint, dust, etc.

If you stay within the current footprint of the home, you should not have any problems.  

Building out is cheaper than building up, and most jurisdictions have a 40% maximum building footprint, meaning that your horizontal space your building occupies on the lot can only be 40% of the lot size itself.

If I were to challenge it I would argue whether the unit was tested by a qualified environmental expert prior to renting and was it tested after the tenant left.  

T-12, T-3, rent rolls updated with current collections, leases, any surveys or environmental reports, repair and CapEx warranty info if any.