I'm looking at getting a 6U rack to mount stuff at the house.  I currently have: 1U router/FW, 1U switch, and a couple of small devices on top.

Looking to add a patch panel and shelf for the smaller items.

For the relatively small amount of stuff I have plugged in do I really need a front cable management panel?  Rack mounted power strip?  Any home use solid 1U ups instead?  Any real difference between a purpose built patch panel or keystone type?

Is there a preferred stack up of everything, or just personal preference?

Planned stack up being:

Shelf
Switch
Patch panel
Router/FW
?
Power

You can get 1500W 1U UPSes relatively cheap - and just to avoid having multiple power cables hanging down I would go that route or at least zip tie a traditional powerstrip in the back.  The order makes no difference, though commonly heaviest on the bottom, or things like UPSes that could have battery leaks on the bottom.  Cable management on a 6U is definitely overkill.  You didnt mention if you are going wall mount telcom rack type deal, or enclosed cabinet (though I have only seen those down to 10U), but keep in mind that depth can be an issue for some switches, particularly POE switches that tend to be longer.

It will be an open type, still in the planning stage and not sold on if I want to wall mount, or leave it freestanding somewhere.  Currently deepest is the router at about 11.25"

I built one like this but taller - https://tombuildsstuff.blogspot.com/2014/02/diy-server-rack-plans.html

On the bottom is an APC 1000 UPS with upgraded batteries.  It's huge and not rack mountable.
Next is a 3U spot for the unRAID server I'm building.  I have the iStarUSA case that can hold a dozen 3.5" drives.
Pyle PDBC70 rack mount power strip.  I like that each outlet has an on/off switch.
24 port patch panel
TP-Link 24 port managed switch
Shelf with a Ubiquiti EdgeRouter Lite / Lenvo ThinkCentre running Pi-Hole
Shelf with my NVR and NVR POE switch
3U shelf with 4 NAS drives (Zyxel, Hawking & Buffalo)
2U shelf with 1 NAS drive & 1 USB drive (Western Digital)
1U empty
4U locking drawer.  I was unsure if I would use it and now it is full of frequently used things like my Ethernet cable tester and my cable crimper.

I just finished my rebuild/upgrade and I will say that racks and safes have one thing in common...  If you think you need one size, plan to go much larger.  In regards to the setup and wiring, it seems like accepted practice is to mount the PP on the top and work the front connections down.  UPS at the bottom with power routed on the right and any data/fiber on the left.  Amazon has bundles of patch cables starting at 6" and a variety of colors so I'd skip any notion of cable management.

Sorry in advance if I end up costing you any money.