I currently work for a multifamily construction company as a Project Control Engineer.

We are still under construction, but I decided to incorporate my own RE brokerage company (as i can do that in NY bc i am a licensed attorney). 

@Teho Kim, local/regional banks and credit unions are usually your best bet.

In general, are there restriction on using SDIRA on a development/construction project...we have a first lien balance around $80k and reno should be $250k.

correct - your fha loan will drop the MI soon  .....HELOC is your best bet ....most lenders want scores > 700 for  helocs ...make some inquiries  and make sure to mention  the mod and the solar panels  when  shopping for  helocs ....I would also  recommend  getting the  heloc in place for the highest amount you can  

LibertyShare or other Health sharing ministries are a good bet.

It depends on the deal and structure; my hard money lender is willing to lend up to 90% of purchase price and 100% of construction costs. 

Remember, real estate investing / construction / this industry as a whole are about building relationships, so treat people with respect and those relationships will grow well. 

We buy at a deep discount and usually acquire with a loan product that allows us to roll in construction costs. 

I have a construction background so the hard labor of the rehabbing is what I look forward to the most.