Even at $60,000 a unit - that is a $1.2 million deal... and realistically I bet they will be over $100,000 each... all just a guess... but when you get into these price points and you are "new to real estate" as your title in your post suggests - I think you are probably getting in over your head for a first deal.  

PG's are worthless those that have PGs that are worth anything dont need gap funding they have the cash.this is a play for folks you know well .. not for internet facebook BP etc.. people that do this do it because they know you like you trust you and think your a good operator.Public has to many other choices that are much safer bet.. its not always about ROI with those with money..

Total investment: $420k, with a 1031 exchange offsetting $300k. 

Wagner used to work with an agent called Jean Gillen and I contacted them about some turnkey properties they were advertising. after some exchange of pleasantries I shared with her that I bought in Ocala in 2017 via another turnkey group and she went on to kinda talk very negatively about how poorly built these homes are.

If you want more cash flow and want to walk away with more of the 80%, perhaps identify another market and do a 1031 exchange so as to not pay capital gains taxes.  

Hey Bigger Pockets community, I'm just starting out in Step 1 (get educated) on what I want to become a successful career in real estate investment.I also currently run an e-commerce business that is currently completely online, but would benefit from having a brick & mortar storefront, and I had an idea that maybe using the investment capital I'm looking to allocate into real estate into a commercial property my business can operate out of until I decide to sell the property in or rent it out to another business.I am obviously very naive when it comes to the complexity of any good real estate deal (especially commercial VS residential), but I'm hoping to spend as much time learning from everyone here who is on their journey as well.My main concern with the idea of buying commercial to operate my business out of it that I might struggle to rent it out afterwards and that there may likely be depreciation in the commercial real estate market over the next 5 years.I understand there is a lot of nuance depending on the local market but I'm guessing commercial is even less of a "safe" bet than finding a solid residential deal to leverage in some way.

I'm 25k out of pocket for permits and clearing.I bet the pre-permitted 10 contiguous lots on the river would appraise for at least 150k.Am i being overly optimistic?

To me, if you aren't at least maintaining 0 cash flow, you're betting too much on appreciation to the investment work. 

Is it possible to do a 1031 exchange and use the proceeds to buy a house using hard money, then refinance into a long term loan?

Security deposit amountYou can find plenty of examples by searching for "tenant estoppel certificate doc" or exchanging "doc" with "pdf" for more options.Here is an example and explanation: Sample EstoppelSome have a lot of legal jargon but this document does not need to be so detailed.