I've looked at rentometer, craigslist, hotpad, zumper, and other sources out there.

I use propstream for one source of leads and to do smaller post card mailings.  

You should also ask where they source their data from.

I wrote a detailed post on Reddit about how I passed the CA brokers exam without paying for any course (only used free study sources in other words).

Does anyone have any advice on funding or sources of money which might help me through this issue?

Save money on paying rent, building equity and creating a future revenue source How did you find this deal and how did you negotiate it?

Does anyone have a good source of long-term rental data? 

Your CPA would be the optimal source of information.

BiggerPockets and Facebook groups are also terrific sources of networking, which have become even more useful throughout COVID.

I am still in acquisition mode and not in a great position to peel off some of the deals I'm currently sourcing as I'd probably have to back them on their first few projects financially at some level.