Due to seller's financial needs however, a full cash-out offer was ultimately agreed upon, and a conventional commercial loan with a 10 year term amortized over 25 years with 27% down was secured.

But what am I supposed to do in this situation that I'm in where I feel like I have no security that he has my best interests at heart?

They secure the money they lend to you with the asset.

I secured the HELOC and have been actively hunting for our first deal (my dad and I).

Typically these type of dispensaries have heavy security and I am not aware of there being any issues regarding theft, etc in the several years Colorado has had MJ approved for recreational use.

Money isn't abundant and I'm no where near financially secure.

Expect some mistakes and redo's along the way to add to the time.Expect any government inspections to add to the time.If you can keep the same team all the way through by the time they get several units under their belts they may be able to go faster--providing they can get the materials.In my opinion, it's more intuitive to look at each unit as a separate job, vs demo all kitchens and tubs in X units as a job.They can still come and demo several units, just for me it's seems easier to keep the Tiger by the tail this way.If you buy all of the materials at once, you will have to guard them against theft and store them somewhere. 95 toilets going missing probably won't tank your budget, but it might tank you enthusiasm for a while.Make sure to budget for a dumpster if you need one, and porta-potties for the workers to keep them from using the ones in the units. 

That is what i'm seeing now, are you familiar with having a seasoned investor with those requirements sign as a "Guarantor'' on the loan to get qualified and secure the funding as a newbie investor?

Think of all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.

Portfolio means that the lender will hold the loan on their books and it will not be sold off to the secondary market (Wall Street as MBS or Mortgage Backed Securities).