Masculine nouns NOT ending in /ā/ do not change their forms in the plural.
1 kelā, 2 kele (1 banana, 2 bananas) - change
1 seb, 2 seb (1 apple, 2 apples) - no change
What is your nationality? I can see if, for example, you have a background in Pakistan you might have the intuition to expect "vo," but in this case, "ve" is indeed correct for Standard Hindi.
No that translation lacks the verb. The sentence वे तीन आदमी हैं। Those three men are., they are three men.
Those three men would be वे तीन आदमी without हैं and that wouldn't be a sentence so would not have । (the danda, devanagari full stop/period)