I'd like to start small with 1-2 STR tiny house(s) or other less expensive "alternate housing" options (yurt, airstream, etc).

One property in particular has 4 years left on abatement but the 2019 assessment is 243% higher than 2018's, and all of the other houses on the block show similar assessment increases. 

If you pair the dropping of the rates and same amount of inventory with letting the population get used to 6-7% rates then drop them back in the 5's the market will be flooded with buyers again. 100% agree here.

If you're trying to buy a primary, househacking with a multifamily purchase MAY help with the DTI situation - it will just depend on the income from the non-primary unit(s). 

I've only done 80% CLTV HELOANs (not HELOCs) on investment properties, but that's not an interest-only loan and usually rates are in the 10's at that high of a leverage. 

Simple answer, yes these are all normal things to utilize.However, as to how they are used - that will depend entirely on where you are going and what you are trying to accomplish.For tax purposes, given it is generally a bad idea to use an S-Corp or C-Corp for holding real estate, any other tax structure will have absolutely no difference from one another - IE an LLC taxed as a partnership, an LLC wholly owned by you and disregarded for tax purposes, owning directly, or owning through a revocable trust - all of these have the exact same tax result at the end of the day.

But #2... since I do them myself I know they are done right and everything gets looked over and fixed and I know every nook,cranny, and potential future issue(s) about my houses.

There's a very good chance the issue(s) you face have already been discussed and answered.Ask questions in the appropriate forum.

Between me and Kevin S  I haven’t heard back from him if his side of the thread wa deleted as well  

. 🤷‍♂️ ““WHEREAS, on Sales Day, the ninth (9th) day of October, 2022, the Delinquent Tax Collector did, during the usual hours of sale, after due advertisement, sell the said property of the said John Doe, tax defaulter (s), to James Doe, his heirs and assigns, the purchaser (s), hereinafter known as "grantee (s)", and the highest bidder at such sale, for the sum of $XX.xx and gave a receipt for the total amount of said purchase money to him; andWHEREAS, more than twelve months have elapsed since the date of said sale and the defaulting taxpayer (s), and grantee from the owner or any mortgage or judgment creditor have failed to redeem said land so sold for taxes:NOW, THEREFORE, KNOW ALL MEN BY THESE PRESENTS, that I, Jill Doe., Delinquent Tax Collector of and for the County and State of aforesaid, in consideration of the premises, and the sum of $xx.xx paid by the said grantee(s), James Doe have granted, bargained, sold and released, and by these present do grant, bargain, sell and release unto the said grantee(s) James Doe and his heirs and assigns. “”