I'd also recommend reading David Greene's book on BRRRR investing as it goes over in much more detail the different lending options and considerations for BRRRR.

I always ask my set of questions for vetting a lender, but since this lender is a bit different I wanted to ask the community what are some considerations to look out for and some good questions to ask?

But a key consideration is having cash reserves after the down payment too.

When getting pre-approved, are there any considerations when shopping approval & interest rates from different lenders?

I started typing up a lengthy post to outline all the considerations when building two houses on a single parcel ... but then I aborted the effort.

.)- Median Rents by Number of Bedrooms- Unemployment Rate- Employment Sectors Percentages These are just some of the indicators that will help you understand the quality of an area as well as the kinds of returns one is to except.Also take into consideration the direction in which each of these market indicators are trending.

Another big consideration when doing BRRRR is the chance of not being able to refinance the property after its been rehabbed and rented due to things like too large of a debt-to-income ratio, so be careful of that when looking into refinancing your current townhouse as that would likely increase your debt-to-income ratio. 

Most investors would choose a SFR over a condo but it is important to take into consideration the location, demand, population, and, most importantly do a investment property analysis on each target poroperty to determine potential profit.

or external trigger (ie got fired from your job)?

My consultation is around this topic and hope that any resources, concerns, consideration or experiences can help.