Sounds like you have no case, your neighbor won't trim their plants and the previous owner of your property  (who is not the neighbor) said they would. 

(New mulch, some light weeding, some new plants/bushes).Anyone have experience in this sort of thing?

Sounds like you have no case, your neighbor won't trim their plants and the previous owner of your property (who is not the neighbor) said they would.

I knew he had rentals and it was a chance to 'plant a seed' that when he is ready to sell I want to talk.

Sewer - City, or Septic, or Plant?

@Jingwen Dunford I hear you, I'd like to outsource landscaping for my rentals too but I have yet to find a cost effective option so I mow, trim and spray myself and keep the plants and flowers beds to a minimum lol.

Can anyone recommend investor-friendly realtors in Polk County (lakeland, plant city area) ?

Meaning, that forging the relationship for the future by my seed planting was greater than the communication mistake.

Repairs of about $15,000 (Texturing some walls, replacing all flooring, maybe new cabinets, one wall will need sheetrock installed, some new sections of hardy plank on the exterior, painting the exterior, some work in the bathroom such as painting and flooring)Our realtor claims that the selling agent won't budge on the price.

This way, you already have planted your first seed which will grow to a tree with many other branches (aka referrals).