Switching from Homegroup to Workgroup - Basics

I've done searches on the topics of homegroups and workgroups, here and elsewhere, and read threads until my eyes have glazed over, but there are still some points I'm missing. Normally, I can research and figure this stuff out on my own, but I'm at the point now that the more I read, the more confused I get.

Up to now, I've used a blend of homegroup and workgroup on our network, but it's not working as well as I would like (access issues between certain computers/users, security concerns), so I'm considering switching to a workgroup only and getting rid of the homegroup altogether.

My network setup:

3 laptop computers running Win7 Pro SP1 64bit on WiFi
1 laptop computer running Win7 Home Premium 64bit on WiFi
1 desktop computer running Win7 Home Premium 64bit on WiFi
1 desktop computer running dual-boot Win7 Home Premium 64bit and Linux Mint on Ethernet
2 HP printers, both of which are available to the network via WiFi; one is also connected via Ethernet (each of them is also connected via USB to one of the two desktop computers)

There is also an assortment of XBoxes, Android phones, and Android tablets connected via WiFi.

At some point in the near future, I plan to add a personal cloud drive that I would like to be available to the entire network, as well as to the laptops remotely as needed (if I can do so securely).

The router is secured (WPA2-PSK) and MAC filtering is enabled.

All computers contain data partitions that are separate from the Windows partitions, and all Libraries (Documents, Pictures, etc.) are redirected to the data partitions. Each computer has a unique name, and the network is designated as a home network.

The hidden Administrator account is enabled on all computers, with the same username and password for all. Guest accounts are turned off on all computers.

My kids like to play games (Minecraft) across the network, and occasionally a non-local sibling also joins in remotely. Minecraft access is controlled through a whitelist.

My goal:

For all computers to have read/write access to the data partitions of all the other computers/printers on the network, while denying access from outside the network to any unauthorized computer/device.

My issues:

1. I sometimes have trouble accessing files on one computer from another, even though logged into the hidden Administrator account on the accessing computer (messages saying that I need administrator approval to move a file on the other computer, for instance).

2. My husband (a standard user) often has to have administrator approval to access a file/folder on his own computer FROM that computer while logged into the account that the file/folder belongs to.

3. Attempts to share folders across the network are often unsuccessful (no error messages, just seemingly ignored).

4. I'm not completely at ease that the network and its devices are as secure as they should/could be, that there is something somewhere that I'm missing that could give an unauthorized individual (outside the network) access that I don't want them to have.

I'm at the stage where everything is so jumbled up that I'm not sure what settings pertain to homegroups and which ones pertain to workgroups. I've found numerous tutorials for setting up homegroups, but the ones for workgroups are incomplete at best, and they don't address "best practices".

My questions:

Is there more to getting rid of the remnants of the homegroup, other than leaving the homegroup on all computers and then deleting the homegroup on the host machine? Any services I can disable that pertain to only homegroups?

Can someone walk me through all of the settings for workgroups, just to make sure I have all the bases covered?