Year of update of the systems (roof, plumbing, electric, heat)4. any pets, pools, tranpolines, or business use at any locationThey will usually need more specifics but this is a good start. 

Should I put in split air for ac/heat? 

I would go for the #2 scenario as the market is expected to pick up quite a bit this summer when rates should drop and more buyers that have been on the sidelines come back in and heat it back up.

Is the current tank shot or just the heating elements?  

Its good to have a crawlspace vented, but less than ideal in winter time when air is dry anyways and cold because you are trying to heat your house.

Heat will be soon.

Anyways in Dec or Jan , bathroom pipe burst because they never switched on the heating or power, or shut down water - during the coldest winter Seattle has ever seen.

To kickstart this project, a comprehensive home energy audit is on my agenda to craft a strategic retrofit plan that significantly enhances operational efficiency by 40-70%.This endeavor seeks to diverge from common quick fixes, such as installing baseboard heaters, which merely shift heating costs to tenants.

Weve had a lot of set backs from issues the seller didnt disclose or else id just have one customed made... instead putting in a french drain in and replacing our AC/heat came first.

This is the simplest method, but it also means your tenants are more likely to abuse the utilities by leaving windows open with the heat or A/C running, leaving lights on, ignoring the toilet that constantly flushes on its own, etc.3.