I had the flooring changed to vinyl planks due to previous bad carpets and then furnished the property and did other minor renovations, had a friend take some pictures and made an Airbnb.

Is it common practice to just charge for carpet cleaning? 

Sometimes you can ask them to include stairs carpet or upstairs carpet replacement/wash as tenant may have used carpet with wet/gray water to move belongings etc.

Has anybody got any experience of tidying up a messy situation like this?

As far as finding a fixer upper I was mainly looking for a property that is more cosmetic repairs like flooring, carpet, paint...etc.

You may find a home in this same area priced 20k cheaper but with older capex items, carpet and other deferred maintenance items that may need to be replaced sooner then later.  

High end interior wood doors with glass panels. new carpet, all new electrical. new bathrooms. breakroom for all tenants.

Everyone else on your team will be transaction-based and not really involved after a purchase.We're in the Metro Detroit area, so you may want to follow our blog here on BP, but at least read the following posts:Follow our "Deep Dive" series we're doing about Metro Detroit cities and City of Detroit Neighborhoods: https://www.biggerpockets.com/...How to “Screen a PMC Better than a Tenant”: https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesIn our experience you will need to:1) Learn to "Maintain to the Neighborhood", not your personal standards2) Tenant-Proof everything you can Hard surface flooring, not carpeting (too easy to trash) Same basic paint for everything No garbage disposals for them to break Only spring-type doorstops also with plate on the wall Glue rubber mats under sinks to prevent water damage Sheet aluminum on walls around stovetops, for easy grease removal Towel racks - screw 1x3 to wall studs, then screw rack to that Install low-profile downspout ext, not aluminum that always disappear Plan on cleaning gutters and leaves up in the fall as tenants won't Avoid garage door openers3) Have a great application screening process: Check credit for evictions & convictions, utility collections Focus on employment/income stability Require bank or debit card statement - you'll be surprised what they spend their money on!

The advantage of the Solo 401(k) is simplicity of administration since you are not managing other people's retirement savings.That said, it can be messy to have partners in a Solo 401(k), just like all things involving partners are more complicated. 

Everyone else on your team will be transaction-based and not really involved after a purchase.We're in the Metro Detroit area, so you may want to follow our blog here on BP, but at least read the following posts:Follow our "Deep Dive" series we're doing about Metro Detroit cities and City of Detroit Neighborhoods: https://www.biggerpockets.com/...How to “Screen a PMC Better than a Tenant”: https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesIn our experience you will need to:1) Learn to "Maintain to the Neighborhood", not your personal standards2) Tenant-Proof everything you can Hard surface flooring, not carpeting (too easy to trash) Same basic paint for everything No garbage disposals for them to break Only spring-type doorstops also with plate on the wall Glue rubber mats under sinks to prevent water damage Sheet aluminum on walls around stovetops, for easy grease removal Towel racks - screw 1x3 to wall studs, then screw rack to that Install low-profile downspout ext, not aluminum that always disappear Plan on cleaning gutters and leaves up in the fall as tenants won't Avoid garage door openers3) Have a great application screening process: Check credit for evictions & convictions, utility collections Focus on employment/income stability Require bank or debit card statement - you'll be surprised what they spend their money on!