The figures are based on the 2 Prussian Artillerymen and one Prussian infantryman. The conversions are fairly obvious.
The 'shovels' are from Irregular Miniatures SW20 Farm Implements. Gripping Beast also make a set of tools SC62 12 tools for £2.00, as do Essex Miniatures X52 which includes Hammers, shovels and picks 8 tools for £2.50. Prices exclude p&p. I am sure there are others out there, but these I have used in the past. One set of tools allows you to make up a number of 'pioneers'.
My latest messing about is to make a third gunner for the Prussians, Bavarians and Wurttembergers artillery crews. I always think they look a bit odd with only 2 gunners/poses. This one will be holding a rammer and will be a conversion of the gunner with the shell.