I saw and heard these words in a video in my history class last year but my teacher didn't elaborate on what they meant. In the context of the video, it sounded as if they were social positions or jobs. At the time, we were learning about the Vikings and the High Middle Ages in Europe.
In Sweden, the equivalent grades of freemen were simply bönder and odalbönder, defined under the "odal" concept. Odalbönder owned their land, and that land would generally have been inherited within their family for some generations. The bönder were freemen who rented their land.
The concept is expanded upon in the Swedish Wikipedia article Bondeståndet i Sverige.
I'm not familiar with the term "Heathguard", however a quick Internet search suggests that the term is commonly used by wargamers for small bands of warriors.
I would suggest double-checking the spelling, since there are a few possibilities (although none wholly convincing). It looks like the word "Heathguard" might derive from either the Old English / Norse word "heaðo" meaning "war", the word "hirð" meaning "retinue", or even the word "hȳrian" meaning "hired". The first two might suggest a personal bodyguard in battle, while the third may indicate a "mercenary guard" in this context.
Note the root of the English word "guard" is actually French, rather than Anglo Saxon / Norse.
Edit 15 March 2020
On further reflection, and having re-read a few of the texts, I suspect that "heathguard" in this context should probably actually be "hearth-guard", in which case it is probably a rough translation of heorð-genēatas, which is more-commonly translated as "hearth companions".
The term appears, for example, in the Anglo-Saxon poem The Battle of Maldon and in Beowulf, and from the context it is clear that the heorð-genēatas were a kind of bodyguard for whom deserting their lord in battle was the deepest-possible dishonour. At the Battle of Maldon, Byrhtnoth's heorð-genēatas continue fighting (to the death) after Byrhtnoth fell, even though many other survivors of the fyrd had fled following the death of their lord.
The Anglo-Saxon heorð-genēatas may thus be more-or-less the equivalent of the Scandinavian huscarls (the term huscarl doesn't appear in Anglo-Saxon England until the 11th century, following the conquest by Cnut Sweynsson in 1015/1016).
I believe Heathguard is a related to the common surname name "Heyward".
The "W" and "G" sounds are related between German and French: "Ward" => "Guard" just like "William" => "Guillaume"
A "Heyward" is someone who guards property lines.
Source for "Heyward" is History of the English Language podcast. Might be episode 117.