For example, if you don't specify if a certain item is reoccurring or 1 time, you can't collect it.

Just so those newer to syndicating (like OP noted) are aware that there many flavors of syndicators, and that "who" is running a deal may not be who one thinks it is, depending on how the items are enumerated.

But enough to make to do all the cosmetics along with a few major items like HVAC, appliances, etc.

Pack their items, change front door locks and give new locks to other tenants.

Reassess whether you need the home warranty, flood insurance, or other items.

Due to item 1, adding an ADU can require years to start achieving any return (once the accumulated cash flow recovers the initial negative position).4) Adding an ADU is a slow process.

I could completely be misunderstanding the process, so thank you, in advance, for clarifying these items for me.

I figure the ones over 50 or 60 years old have already had all the big ticket items replaced.

Good summary of what your market is looking for but as we all know, each market tends to have its "wish / want" items which differ from market to market.Flow is definitely a selling point but make adjustments come with a cost. 

I would only recommend purchasing items that fall into that vision.