And get a sewer line scope - if the house is newer and you have proof that it has PVC pipes, you might be able to skip this but to be cautious always get a  scope.

Needs some light exterior work (paint, caulk, broken vinyl siding).

After 3-5 years on average you have to expect a few things to do and we also take the opportunity to do some upgrades.The range is wide: we just had a tenant move out after 10 years and they left the home in great condition, but had to replace 2 vinyl windows that had broken thermo seals, replace the kitchen vinly floor with LVP and upgrade some of the light fixtures.

My contractor eliminated a window in the kitchen and pulled some vinyl siding from the garage to replace. 

No contest between cast iron stack mains and PVC.

HVAC duct work insulation is also deteriorated.No vapor barriers installed eitherSome fungi/mold growth notedPlumbingMultiple small leaks under sinks and from bathtub and toilets.House has Polybutylene plastic plumbing which is dangerousMain shut off valve is damagedElecticalSome small exposed wiring and bad splicing.Whole house has no GFCI's or grounding outletsInteriorMoisture spots on ceilingExteriorLose Vinyl SidingDoor Jams and Window trim have moisture damageDriveway need replacementRoofingMinor leaks noted in atticRecommended to replace roof covering, but not whole roofSome fungi growth noted in roofSo some of the question I am trying to tackle with this work is:How much should I budget for the main issues listed? 

We did use a high-grade vinyl plank flooring over the concrete floor down there, just in case, but years later we can say there have been no more water issues.We also plumbed in and installed a laundry room, purchasing twin pairs of coin-op Speed Queens.All of those renovations allowed us to go up-market a bit, from the prior $160/week to $180/week within the first few weeks on the incremental rehabbed units.

The particulars are:Total SF: 5160Roof: Shingles, replaced 2001Plumbing: Mix of PVC and Copper, updated in 2014-2023Heating/ cooling: forced air, 3 furnaces replaced in 2014-16, one AC replaced in 2014Electrical: has been updated periodically from 2014-2023.

Initially I wanted to use vinyl snap together flooring since it is pretty durable and I have worked with it before.

When I used vinyl surrounds, yes it was much cheaper, but I had to replace almost every turn over.