Can you sell your house and buy it?
Personally, if I was going to take something like this on I would only do it with leveraged money. Liquidating assets seems shortsighted, given the information you have provided so far, at least. If you were a seasoned real estate investor who found a can't miss property, then maybe cashing in your 401k makes sense?
Are you experienced in real estate investing and landlording? The fact that it has a long time owner in one unit and nine units empty tells me that it will need some updating.
Maybe a lot of updating. Multiplied by ten!
Where will you get that money? And the tax bill for liquidating your 401k would wipe out your yearly savings.
The way to do it cost efficiently, IMO, if you are going to actively manage and fix these units yourself (can you do repair work?) would be to renovate one or two units at a time and rent them out to improve your cash flow, and then repeat.
But you could easily spend $10k per unit. Or way more if the building needs major work. Way, way more!
So I would get a handle on what the repair costs will be, first, by getting actual quotes, if possible, or at least walk through with some contractors to get a sense of what needs to be done. And then break that down to: what you can do, and what you will hire out.
A project like this could easily get out of hand, financially, if you can't make your monthly payments. It's one thing to think "oh, it's worth this much, and the monthly rent will be this much", but you have to be able to make your monthly payments throughout the project, for years, likely.
As to how to re-fi, go talk to brokers now and ask them what they would need to see from you to refinance.
So as not to discourage you too much, my BIL (partner in law?) is doing just this, but an 8 Plex, and loving it. Retired early schoolteacher, wife still working. They sold their house and moved into one unit and are slowly renovating the other units.
Eventually they will probably sell it, but I haven't talked to him about his long term plans. He needed something to keep him busy, lol. He's doing the majority of the work and hiring professionals as needed.