You sure do present fun challenges for my "computer breaks!" After reading your reply, noting that you intended to check out the Civil War records of the Hull brothers, I travelled through my subscription databases again. Here are their records. Now, I PROMISE I won't do anything else, so you can all the fun of taking your search further from here :)
The following information was taken from these resources:
(1) Civil War Service Records
(2) Civil War Pension Index
(3) Minnesota Civil War Soldiers
AARON P. HULL, resident of Greenbush, Sheboygan Co., WI:
Enlisted as a Private on 1 June 1861 in Company B, 8th Infantry Regiment Wisconsin on 1 June 1861. He received a disability discharge on 19 February 1862 (at rank of Pvt.).
Sheri, his brother Daniel enlisted with him on the same day:
DANIEL HULL, resident of Greenbush, Sheboygan Co., WI:
Enlisted as a Private on 1 June 1861 in Company B, 8th Infantry Regiment Wisconsin on 1 June 1861. He was killed in battle on 16 December 1864 at Nashville, TN.
A side note says: Gen. Sherman highly complimented the 8th Wisc. regiment for doing "its whole duty in the camp, on the march and in battle," for "Pecular courage and gallantry at Jackson and throughout the siege of Vicksburg," and for other services.
According to the Aaron P. Hull's pension record, he followed his WI enlistment with a tour in the following MINN. regiment:
HULL AARON P., born Canada. Residence: Greenbush, Sheboygan Co., MINN [sic].
Enlisted as a Private on 22 April 1864 at the age of 21 in Company D, 4th Infantry Regiment Minnesota on 22 April 1864. He mustered out on 19 July 1865 in Louisville, KY.
A soldier named Cornelius Hull was in the same 4th Infantry Regiment Minnesota that Aaron joined in 1864:
HULL CORNELIUS, born Canada. Resident of Rice Co., MINN. Enlisted as a Private on 14 October 1861 at the age of 22 in Company I, 4th Infantry Regiment Minnesota. He reenlisted in Company F, Minnesota Veterans Reserve Corps., 4th Infantry Regiment Minnesota on 1 January 1864. He mustered out as Pvt. on 19 July 1865 in Louisville, KY.
Reuben, however, seems to have fought for an OH regiment?:
REUBEN E. HULL:
Enlisted as a Private on 3 January 1862 at the age of 23 in Company H, 80th Infantry Regiment Ohio on 13 February 1862. He was promoted to Full Corporal on 4 January 1864. He was promoted to Full Sergeant on 19 June 1865. He mustered out on 13 August 1865 in Little Rock, AR.
Noting that Aaron and Daniel Hull were both residents of Greenbush, Sheboygan Co., WI at the time of enlistment (1861), I checked the 1860 census for Greenbush for you, Sheri. Here's their Hull family at that time, in case you don't have it:
HULL, William, age 48, farmer, b. CAN.
HULL, Amanda, wife, age 43, b. CAN.
HULL, Daniel, son, age 19, b. CAN.
HULL, Moses, son, age 17, b. CAN.
HULL, Aaron, son, age 15, b. CAN.
HULL, Almira, daughter, age 14, b. CAN.
HULL, Reuben, son, age 12, b. CAN.
[Cornelius was apparently out of his parents' house by that time].
NOTE: If Reuben was the same Reuben E. Hull who fought for OH, he certainly lied about his age when he enlisted (many young men did). The only other Reuben Hull in the Civil War Service Records fought for West Virginia.
The Civil War Pension Records give the following information on the Hull boys:
AARON P. HULL (8th WI Inf. and 4th MN Inf.): applied for his pension on 7/2/1880, from the state of WI. No widow's benefits were later applied for.
REUBEN E. HULL (80th OH Inf.): applied for his pension 12/19/1913 (? year hard to read). His survivor's benefits were applied for by "minor" (vs. widow) Ollie Hull on July 1, ---6 (year otherwise illegible).
CORNELIUS HULL (4th MN Inf.): applied for pension 4/27/1874. Widow Olive Hull applied for widow's benefits (from the state of MN), date/year illegible.
Best to you, Sheri,