With that in mind, I’m considering purchasing four rental units over the next four years to build a stream of income that could help supplement my retirement by age 68.The challenge I’m facing is that the deals I’ve come across so far don’t make financial sense.

Also you seem to be motivated to build since you already have these lots. 

You can use this property to hedge any others that you add that may only cover themselves, or require supplement until they are paid off.HOWEVER, if you have decided that your goal is to use Real Estate as a stepping stone to build wealth by upgrading the property you hold each time (condo to house, house to 4-plex, 4-plex to 8 unit, etc) then I think you are right to sell now while you think the property is at the top of it's appreciation.It will be hard for anyone on BP to tell you what to do as we don't know your goal.You are right. 

I’m excited to learn from this community, share ideas, and build valuable connections.

If you have the sellers, the buyers will start reaching out - it likely wont work for some of them and then you can ask what they are looking for and build relationships that way.

. - Communicate openly and regularly to build trust.

I work at my brothers business as a independent contractor ,  he has an accountant for this business is necessary for him to to this job or i can do it myself.

However, building a relationship on a lack of disclosure or a lie isn't probably the best idea, let alone the ethics of the matter.Hope this helps.

Staying on the same page and building trust.

FL seems to have reigned in HOAs recently, so who knows what they are allowed to do.I know that in CA, an HOA can ban smoking in units because smoking is not a protected class and the HOA has an interest in the safety & health of the building.