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#1 HSRP may make sense. By default, if the Stack master fails, another member switch becomes the gateway IP but the virtual gateway MAC changes. As a gratuitous ARP is sent, most modern hosts will reset their ARP cache, but it can be problem for hosts that don't react to the gratuitous ARP. Two ways to avoid, use HSRP which also has a virtual MAC or use the command that transfers the original stack master's MAC to the new stack master (NB: other considerations with this command also apply).
Another reason for using HSRP, if in the future you wanted to migrate to a new L3 gateway device, you can have it join the HSRP group and take over as the active gateway. (Probably unlikely needed in your case.)
#2 Depends on what you consider STP need. STP doesn't pertain to the stack ring, but you'll likely still want it active to preclude accidental edge loops.
For the 2960s, multiple links would require it unless you use Etherchannel or FlexLinks.
NB: BTW, think original STP is default, if so, enable rapid-STP.
#3 Etherchannel, to the different stack members, would be my 1st choice.
