Installed doors, closets, wide-plank hardwood floors, kitchen cabinets, and custom-poured concrete countertops (island included) myself---DIY.

I even got on my belly and slid around the house smelling every baseboard, wall, door, inside cabinets, but I can't find where it's coming from.Yesterday morning we read the following news article: https://www.codyenterprise.com...This guy had 35 cats next door and the odor is wafting into our property!

We've begun to remodel one unit and we've taken off some drywall and pulled all fixtures from the bathroom, gutted kitchen and bringing in all new cabinets and appliances.  

Repainted entire interior, replaced all light fixtures, replaced all flooring, painted kitchen cabinets and added new cabinet doors, installed granite countertops and 12x25 concrete patio on back of unit.

I've got things like:Paint, replacing carpets, installing LVP (will calculate those by SF), replacing cabinets, installing countertops, purchasing appliances (washer, dryer, fridge, etc.), hot water heater, roofI'm sure there a lot of obvious things that I'm missing and would like to hear them all.

I have no experience in construction so was wondering what would the best option be if I'm only looking to replace kitchen cabinets, counters, floors, painting, light fixture, vanities, appliances?

Those building elements (could be cabinets, fixtures, interior walls, etc.) that are part of the unit would be your responsibility as well as all your personal property (unless the bylaws say differently). 

Otherwise, pretty much normal stuff; paint, flooring, cabinets, doors, fixtures, etc.We spent about $10,000 more than we had planned but in the end, we sold it in just a couple days for $20,000 above listing price.

Otherwise we did what you would expect; carpet, tile, paint, cabinets, granite, new appliances, fixtures/hardware, etc.

Painted 100% of the interior and exterior window trim, replaced the front door, added tile floors in the bathroom and kitchen, painted bathroom vanity and replaced all fixtures, put in new quartz countertops on original cabinets, all new light fixtures, door knobs and handles throughout.