There are a number of other records which support that burial that ciderdrinker found. It's not entirely clear though whether there is more than one William Hemmings of the same age. I suspect these records are all for the same William.
Bedfordshire Gaol Registerhttp://apps.bedford.gov.uk/grd/1845 William Hemmings; age 18; Felony; 6 Calendar Months Hard Labour; res: Toddington; born: Tilsworth
http://apps.bedford.gov.uk/grd/detail.aspx?id=157881845 William Hemmings; age 18; Stealing a Lamb; 6 Calendar Months Hard Labour
http://apps.bedford.gov.uk/grd/detail.aspx?id=77401845 William Hemmings; age 19; Examination stealing tools; disposed: bailed, died at home
http://apps.bedford.gov.uk/grd/detail.aspx?id=8091It's not clear to me whether the first 2 records are for the same person and offence but I presume the first one is regarding the William you're researching Emma.
Bedfordshire archives:Reference: QSR1847/1/5/1
Date free text: August 1846
Title: Depositions - William Hemmings charged with stealing a quantity of tools from John Bigg
Text contains lengthy depositions.http://bedsarchivescat.bedford.gov.uk/Details/archive/110402227Reference: QSR1847/1/6/1/b
Date free text: 12 October 1846
Title: Certificate of conviction - William Hemmings of Tilsworth convicted at Bedford Assizes on 15 March 1845 of stealing one lamb, price 5s, from Edward Horn. Sentenced to 6 months imprisonment with hard labour.
http://bedsarchivescat.bedford.gov.uk/Details/archive/110402255Reference: QSR1846/4/2/2
Date free text: October 1846
Title: Letter from W.R.Young, superintendent of police, regarding material witness in the case of Bigg vs. Hemmings for stealing tools, who has been certified ill by Dr Laurie of Dunstable. Asks what steps to take "as it will be useless going before the Grand Jury without him". Says "the prisoner has been before convicted and is a bad fellow".
http://bedsarchivescat.bedford.gov.uk/Details/archive/110400066Reference: QSR1846/4/3/3
Date free text: 20 October 1846
Title: Return of persons committed, bailed to appear for trial, or indicted at Quarter Sessions held 30 June 1846. Gives names, ages, crimes and result of commitments.
William Hemmings, 19; George Smith 39 - larceny, 2nd offence (Hemmings) and simple larceny (Smith) - entered into recognizance to appear at next Quarter Sessions due to absence from illness of a material witness
http://bedsarchivescat.bedford.gov.uk/Details/archive/110400074Reference: QSR1846/4/3/5
Date free text: October 1846
Title: Return of former convictions of persons to be tried at Michaelmas Sessions 1846
William Hemmings - Lent Assize 1845, stealing a lamb, 6 months; 1846, stealing a sheep, discharged
http://bedsarchivescat.bedford.gov.uk/Details/archive/110400080Reference: QSR1847/1/6/1/a
Date free text: 28 December 1844
Title: Indictment - William Hemmings of Luton for stealing one chisel (value 1s), one bit stock (value 2s), and one pair of pincers (value 1s) from John Bigg. Previously convicted at Bedford Assizes on 15 March 1845. Annotated "Dead see Cert.".
The date of this document (Dec 1844) seems a bit odd, I suspect it should be 1846http://bedsarchivescat.bedford.gov.uk/Details/archive/110402254Reference: QSR1847/1/3/6
Date free text: 28 December 1846
Title: Death certificate - William Hemmings, age 19, labourer, died at Toddington 20 November 1846 of typhus fever. Informant Leah Chance, present at the death.
http://bedsarchivescat.bedford.gov.uk/Details/archive/110402166Reference: QSR1847/1/3/4
Date free text: 5 January 1847
Title: List of cases at Bedford Quarter Sessions. Gives case numbers, names, offences, and outcome.
1. William Hemmings - simple larceny after previous conviction - indicted at last Quarter Session, has since died
http://bedsarchivescat.bedford.gov.uk/Details/archive/110402131Newspaper records:Bedfordshire Mercury
24 January 1846
Woburn
Before Lord C. F. Russell, and Major Gilpin, in Petty ?tty Sessions, Friday, January 18, 1845.
Wm. Hemmings, of Toddington, was brought up in custody of Superintendent Jebbett, charged with sheep stealing, remanded from Friday last.
Superintendent Young said he was not in a position to offer any further evidence in the case.
This article is indexed as in 1846 but this doesn't tally with the date in the newspaper (1845)Bedfordshire Mercury
09 January 1847
Death Of A Person Charged With A Felony
William Hemmings, who had been on bail, and who was stated on the calendar to be charged with stealing a quantity of tools, at Luton, the property of John Bigg, was reported to be dead.
GRO death index references:1846 Q4 Death - William Hemmings; age 19* (b1827); Woburn Union; 06; 104