The options are many and varied;
1941-early 1942 - US Army regulars and Filipino Army troops defending the Phillipines. The US 26th Cavalry had the khaki-tan riding breeches, OD shirts, "dish pan" helmets and M1 rifles, the rest of the troops in the Phillipines used the M1903 bolt-action rifle (along with BARs, etc). There were Marines, also, in pre-war type uniforms. A cluster of National Guard tank companies were organized into the 192nd and 194th tank battallions and were rushed to the Philipines without a chance to train on their new M3 light tanks. There were a few 75mm guns on halftracks as part of the Provisional tank Group also.
1942 - Guadalcanal. The 1st Marine Div. was landed on a logistic shoestring. Troops had green untilities and M1 helmets but the Marines still used M1903 rifles, plus BARs, Thompson and Reising SMGs, and Browning MGs of various flavors. Some Marines were still in pre-war khaki uniforms when landed. In photos one sees that leggings were soon discarded and minimal web gear was worn. Marine Raider and Paramarines also served as ground infantry. Tanks included M2A4 and M3 light tanks, and a few M3 75mm guns on halftracks. First use of LVT but in a logistic role.
1943 Tarawa - many Marines in camo suits or at least the famous USMC helmet cover, M1 rifles are now standard with M1 carbines in use, plus the Thompson, BAR etc. The Reising SMG was unsatisfactory and was removed from service. Tarawa saw use of the M4A2 medium and M5 light tanks. LVT used as an assault vehicle.
1944 saw the introduction and use of the LVT(A)1 and LVT(A)4 "Amtanks" as well as improved Amtracs. Medium (M4A2) tanks generally replace light tanks in gun roles. Some light M3 and M5 types are converted to "Satan" flame tanks. The Marines seemed to fall away from camo suits and go back to green ultilities with camo helmet covers. Navy "Seabees" are a common part of the invasion forces.
By Iwo Jima the M4A3 medium tank is often replacing the M4A2, there are still some M3 halftracks with 75mm guns used for support. On Iwo some units used camouflage schemes painted on their vehicles and artillery.
Over the years the 105mm howitzer replaced the 75mm pack howitzer in Marine artillery batteries. The WW1 French-type 155mm howitzer was replaced with the M1-series 155mm howitzer. From 1942 onwards the 155mm gun (Long Tom) is seen with the Marines. As the M3 halftrack SPMs (self propelled mounts) wore out, by Okinawa the Marines were using M7 "Priest" SP 105s for assault guns.
The Marines used several different types of trucks versus the Army, for instance the common Marine 6X6 cargo truck was an IH instead of the Army's GMC (the Navy and Marines DID have GMCs too).
There are more possbilities for figures as Navy and Marine air groups operated from island bases and lived with the Army and Marine troops.
Don't forget the Army in the Pacific. US Army troops operated in the Southwest Pacific and in the Central Pacific. One US Army tank company used M3 "Lee" mediums in the Kwajelein operation. Other units used various M4-series mediums and M5-series light tanks.
So there are a number of opportunities for different figures, artillery and vehicles in the Pacific.
Gary
