For a multifamily only your % of personal use of the building will qualify for the 121 exclusion (2/5 year rule)So if you occupy 1 unit of a 4 plex (assuming all 4 units same size) 25% of gain can be excludedYou can however combine this with a 1031 exchange and defer the gain on the other 3 units into a new rental property 

For my first investment property, since I do not have adequate funds for a down payment/do not qualify for a traditional loan due to insufficient credit history, I am seeking a partner to provide the down payment while I provide the deal. 

So borrowing now before the market starts to drop may be a good move.If you qualify it may be wise to refinance both properties so that you are cash fluid. 

Must make below $150,000/year to qualify.

Would you need your W-2 job a little longer to qualify for loans?

Unless you plan to pay cash for your properties, get pre-qualified for an investor loan, so you will know how much credit you will have access to.The end goal - This is usually something like $10,000/Mo. income, in present value dollars.Time frame - The shorter your time frame to reach your goal, the more initial capital and credit you will need.Your plan does not need to be complex or in any specific structure.

But, IMHO the same thing happens to these workers that happens to students that are admitted to colleges that they didn’t really qualify for.

If by we, you mean a partnership, then investing in the LLC may make sense, especially if that allows you to qualify as an accredited investor.

Since you occupy one unit- that unit will qualify for the 2/5 year rule (if you've lived there for at least 2 years) for the 121 exclusion and be tax free. 

Think scholarships (even if you don’t qualify for academic ones there’s thousands of random non academic ones if you do the research), community college then state institutions, etc.