hound is a correct tranlation for Hund
No, it's not, at least not reliably. Not accepting "hound" is a deliberate decision by the course contributors, because in today's English, "hound" most often refers to "one of any of several breeds of dogs trained to pursue game either by sight or by scent, especially one with a long face and large drooping ears." (See meaning 1 at https://www.dictionary.com/browse/hound .)
The meaning "any dog" is marked as "informal" there.
See also https://dictionary.cambridge.org/dictionary/learner-english/hound_1 , which only defines it as "a dog that is used when people hunt animals" or https://www.oxfordlearnersdictionaries.com/definition/english/hound_1?q=hound , which says that a hound is "a dog that can run fast and has a good sense of smell, used for hunting". Those two do not even mention the meaning "any dog".
Compare also a Google Images search for "hound" versus "dog".
So accepting "hound" for "Hund" might lead English speakers to conclude that Hund refers specifically to a dog used for hunting, and that a chihuahua (for example) is not a Hund -- when of course it is.
Ein is "one" where eine is "a"... i u derstand that these items can be loosely used the same way. However, in the past several lessons they have not been used that way. This can be a point of frustration, especially when i am trying to teach my 8yo son at the same time i am learning. Just some constructive critisism.
No, it's not true that ein is "one" and eine is "a".
German does not make a distinction between "one, a, an" -- they are all represented by the same word.
But this word takes on different forms according to the grammatical gender of the noun that follows and according to the grammatical case that noun is in.
So just as you say "a boy" but "an elephant" (you can't say "an boy" or "a elephant" even though "a" and "an" means the same thing - you have to choose the right form depending on the following word), so also in German you have to choose between ein and eine not by meaning but by the word that it goes with.
ein is used together with masculine nouns such as ein Mann "a man" or ein Löffel "a spoon"; it's also used together with neuter nouns such as ein Mädchen "a girl" or ein Messer "a knife".
eine is used with feminine nouns such as eine Frau "a woman" or eine Gabel "a fork".
As you can see, grammatical gender does not necessarily correspond to anything in the real world -- girls are female by natural gender but the German word Mädchen is grammatically neuter, and spoons are inanimate objects but are grammatically masculine.