Nice ideas, i have some pointers.
Defib idea: The map is fairly small and with the delay for a "nearby spawn" i feel it is not necessary.
Double Pistol: This defeintly should be implemented. Pistols to be added as primarys and secondarys, but no "bigger guns" as secondarys.
Group chat: Would be great! i'd prefer it as an option not an item.
An idea i've had is more vibrant colours on beginer armour pieces. Example being bright red football helmets, adding the element of wether being more hidden is more important than the limited protection it gives you.