Where have you successfully found reputable, investor-friendly lenders in the past?

They will still match you with CPAs with KNOWN poor reputations and a long history of client complaints/issues as happened with me. 

My recomendation to you is to talk to a few reputable property management companies first, check the zip codes/ areas they work and then start your research from there. 

Many of the tax professionals on this forum are not "cheap" but can make a good fee for fixing situations where investors relied on poor advice from cheap advisors.My conclusion is to interview a few and go with a professional that you feel comfortable with no only their fee, but also their personality, their experience, their reputation, and their willingness to not only advise you as you start your journey but provide education and planning for what type of investor you want to be. 

And how would I go about finding a reputable builder.  

I can't emphasize enough that when working with other professionals, your reputation is on the line, and that of the other professionals. 

Consider pre-loved appliances from reputable stores or online marketplaces.

Don't go cheap and use a reputable, and probably expensive, bonded trustee.

While it may come at a higher cost, for a project involving plumbing, boiler conversion, and termite treatment, my strong recommendation is to opt for a reputable general contractor.

As long as the inspection checks out and the builder has a good reputation, it may be a good idea to pull the trigger on both properties.