Hey Parker!
Here's my thoughts:
1. I definitely would NOT pass on it just because of the size. If it has the potential to be a killer deal, definitely go for it. You'll be able to scale faster this way. However, the lending requirements will differ for commercial so you'll have to make sure you're covered there (meaning you'll need to meet the net worth, liquidity and track record requirements from the lender).
2. I would go to a local bank and start building a relationship with them. Local banks will many times lend on loan to cost as opposed to loan to value which will help you cover the renovation cost. For example, a community bank may lend 80% loan to cost of the entire project which would mean less cash out of pocket upfront and probably cheaper/less risky than HML. In addition, many times if you refinance into a long term debt solution with that same bank to pull some cash out, they'll give you a very low cost to refi.
3. I would say find a contractor you trust that can also handle the project management. 12 units isn't really large enough to warrant a dedicated project manager. The contractor should be able to handle this. Just make sure you interview a few of them and find someone legit.
4. The sooner the better. Some may not want to waste time unless you give them some cash upfront for taking a look, or some might look to do it for free just to build the relationship. However, try to get them in ASAP. i.e. during the beginning of the due diligence period. Or, you could have them walk the property even before placing an offer if you're there walking it yourself. Either way, the latest you'd want to have them is probably early in the due diligence period so you can make sure to accommodate anything that pops up or if you want to get different opinions on the job. Section 8 units tend to be pretty simple cosmetically - paint, floors, basic cabinets, basic bathrooms.. so it shouldn't be anything crazy, but always try and get them in early since many times you might end up having to switch contractors.
5. The property probably has something going on that you haven't seen yet. If a few units aren't livable, are there serious mechanical, electrical or plumbing issues going on that will be a huge expense? Are there serious pest issues? Is the neighborhood a war zone? You'll have to take a look at the property in person and identify what's going on. Maybe you get lucky and there's nothing crazy bad, but I'd say if it's a steal and it's been on the market for a couple months, there are probably some unseen hurdles.
Hope this helps!!