What questions should I be asking, what should I be looking for and what should I watch out for as a future investor while searching and interviewing sponsoring brokers?

I read a few of the posts and would recommend talking with a lender in regards to the multi unit property since so far you have only watched videos on YouTube or podcasts.

Move slowly and carefully and watch for booby traps.https://allthatsinteresting.com/collyer-brothers

Took me many times of watching it to finally order the course. 

The #1 determinant is the Tenant Pool.If you don't believe us, try putting several Class D tenants in Class A apartment buildings and watch what happens.

Get informed about real estate investing by watching videos.

And you've joined one of the best communities for all things real estate investing.1️⃣ Download this ultimate beginner’s guide: https://assets2.biggerpockets.com/uploads/user_file/file_object/1694/UBG_2018.pdf2️⃣ Read BP beginner books on investing: https://store.biggerpockets.co...Also, read Rich Dad, Poor Dad by Robert Kiyosaki and Think and Grow Rich by Napoleon Hill 3️⃣ Subscribe to BP podcasts or YouTube channel and watch their webinars. 4️⃣ Ask questions here on the forums.5️⃣ Visit (join) a local (and legit) real estate investment association.6️⃣ Consider joining a BP bootcamp: https://www.biggerpockets.com/blog/real-estate-investing-bootcampsI wish you all the best in your investing journey!

As you read these books, watch the BiggerPockets podcasts.

As any gambler knows:https://www.youtube.com/watch?

I've been watching the appreciation and collecting rent ever since.