Not having these inspected would be a Red Flag for most and I've seen where it substantially affected the property value.....

His inability to get bank financing is a red flag to me.

A Comprehensive Guide to Homebuying, it's essential to be thorough and methodical to ensure you're making an informed decision but draw boundaries, it's okay to open built-in closets and kitchen cabinets to assess the property, However, respect the seller's privacy by not invading their personal space, such as medicine cabinets, storage boxes, or clothing drawers,Interior:Architectural style.Bedroom and bathroom count, size, and location.Closet and storage space.Number of floors.Sightlines and general floorplan.Appliance age and condition.Light switches and socket count.Plumbing and water pressure.Natural light and views.Noise levels.Stairway width and type.Porches and decks.Garage and parking capacity.Proximity to neighboring homes.Remodeling opportunities.Exterior:Roof and siding condition.Landscaping and outdoor maintenance needs.Additional Considerations:Take notes and photos during the tour.Use your five senses to assess the home's condition.Ask your real estate agent questions about the home's features, flaws, and market conditions.Red Flags:Overly scented rooms.Water stains and damage.Lack of maintenance.Foundation issues.Sagging ceiling.Fresh paint that may be covering up issues.Final Tips:Be prepared to make multiple offers before finding the right home at the right price.Stick to your budget when making an offer.Don't overlook potential red flags just because you love a home.

Sean :D I think it would raise a red flag if Sean came on and claimed to be the final and best authority on all things wholesaling, what's wrong with recommending someone else's material?

A buyer's inspection will likely flag knob and tube wiring as a fire hazard. 

While the issues you mentioned sound completely fixable, it's a big red flag that it failed the fire inspection.

Can you experienced investors share some insights on what factors are crucial to analyze and what red flags to watch out for?

It was a huge red flag, so we immediately changed our offer.Trust is essential in real estate, and if you don't trust the seller, walk away.This anecdote taught me significant lessons.

Anytime a tenant is nasty with our staff it is a huge red flag.

"Cannot" in this sentence as a red flag.