"They are as strong as us."
Translation:Loro sono forti come noi.
If you wanted to use that sort of construction, you would say (Loro) sono così forti come noi or (Loro) sono tanto forti quanto noi.
Doubtful .... Tanto means 'many' or 'lots'. Neither are mentioned in the phrase.
"forte" is the singular form for either males or females. The same happens in the plural, where "forti" is used for both genders.
Could this also mean "they are strong like us"?