Alan,
The MKE market is hot right now and has been all summer. It's a sellers market. With that being said I'd recommend you buy now anyways. Barring a completely atrocious deal, you will come out ahead when you're living rent-free in a cash-flowing house-hack. Rent is expensive in MKE.
The inherited tenants could be an issue, but it doesn't have to be. Since you are going to be house-hacking the place you will get a good feel for who your tenants are as people pretty quickly. Read through the current leases and understand the terms. Also, just talk to them and try to understand any issue they have with the house. Everyone appreciates being heard. As a landlord you are in the service industry as well as the real estate industry. I also would try to get the previous owners rent roll or payment record to try and identify tenants that may be problem-childs or have habits of late payments. Lastly, in Brandon Turner's book on managing rental properties he talks about sending the current tenants a letter or email explaining who you are and how you run your company. I would highly recommend this as well. Start out on the right foot from day one. Also, read that book if you haven't.
On street parking is very common for Milwaukee and unless you live downtown it really isn't all that bad, just inconvenient.
Prior to the inspection, I would go on the county website (https://lio.milwaukeecountywi....) and check out what kind of permits were pulled on the property and the county records. Just type the address in and click on the Assessment Info. Then click on the tax key and permit info. Knowing what permits were pulled and the property record has a few advantages. First, you can see what work was down on the property and who did it. Knowing what companies worked on your property can give you an idea of the quality of work. Are the contractors still in business? What do their reviews say? What are their ratings on the BBB? Make note of all of this and have your friend look at them during your inspection. If everything looks kosher, you just found yourself a contractor you can use on your property in the future. Second, during your inspection make note of anything that has been updated but didn't have permits pulled for the work. If the electrical boxes or plumbing look updated but no permit was pulled this is a huge red flag. Electrical fires caused by incorrect wiring are not covered by insurance so this could be a serious problem. Most of the time its just small things though, like a fence or retaining wall. It helps to have a good understand what work requires permits in Milwaukee. This can be found on the county website as well. Finally, when you pull the records you can see what kind of citations were issued on your property and how the previous landlord ran things. If they tons of citations for bushes over-growing into the alley or sidewalk you can guess they were pretty hands off and maybe didn't give the property the attention it needed.
For the inspection I would just use this post (https://www.biggerpockets.com/...) by Mindy Jensen as a checklist as you go through. Be very thorough.
Buying your first investment property is an exciting time and a great step towards wealth. Feel free to PM if you have more questions about the home buying process or personal finance ($17k in Bitcoin?!?! I get the feeling you love volatility lol) Good luck and happy investing!