"On Friday you will see my uncle at your house."
Translation:El viernes verás a mi tío en tu casa.
The functions are similar, but there is a difference in grammar. When you see "vas a", you should always translate it as "going to" before "will". Verbs in the informal second person that translate directly into "you will [do x thing]" generally ends with "ás" (verás = you will see, irás = you will go, harás = you will do).
No, because "my uncle" is already present elsewhere in the sentence, so it doesn't make sense to have a pronoun representing it earlier. If you were to translate what you have, it would come up as "On Friday you will see him my uncle at his house" ('his' house because the possessive pronoun 'su' doesn't match the informal singular '[tú] verás', so one is forced to assume it refers to the uncle).
If anything, there would need to be a pronoun for the person being addressed (tú/usted/ustedes), but even that isn't strictly necessary due to there being implicit pronouns as long as the verb is present.