For spec loans to new LLCs, the lender will likely require your personal guarantee (your income, credit, bank accounts, etc.) and might require you to be a borrower and hold title, as well as your new LLC. Not all, but some lenders will. Depending on the lender and their underwriting, they might lend a certain % of construction cost only (you need to bring in the equity with the lot/land/dirt), or a % of total construction cost including the lot or a certain % of ARV.
Some might roll in closing costs, some won't. Some allow for interest reserves, some don't. They want to see a good amount of reserves in the bank, after closing. For a newer LLC borrower, they will likely want to get to know you (talk them through your experience, show your past projects, what you plan to do, what your numbers look like, what you have going on right now, your knowledge of that specific market, etc.). They will want to know who the builder is and their depth of experience, as they need to be vetted by the lender, as well.
Each lender is different and will have a different set of guidelines. Lending criteria will not only differ by lender, it might vary based on how well the lender knows you or if you already have some sort of relationship with them (maybe you have had prior loans or bank accounts with them, etc.).
Best way is to reach out to them and get a feel for what the lenders are looking for - what types of projects interest them, what is their lending profile, etc.
Best of luck!