Nice update!
I think you should aim to hire Marrs and Trent permanently, make it a decker/mage/samuari group, for maximum flexibility, though Ricky has been useful. I just don't trust d0rfs..
Joshua should be focusing on computer skill and build firearms on the side. Probably put some points towards negotiation as well, to make prices lower.
The samurai should build body to soak damage, and combat skills to deal it.
The mage should build sorcery skill almost exclusively, but take some willpower as well to soak mana drain.
You'll be wanting to upgrade Joshua's decking gear, Marrs implants, especially wired reflexes and body armour would be useful. Trent should focus on getting better and more varied spells, possibly a power focus if one is available somewhere? Those are ridiculously expensive, if they're priced anywhere near what they are in the PnP game, yet they're also immensely useful.
And it should almost go without saying, in Shadowrun, you can never have too many contacts.
So, Decker, Mage and Samurai.