I always used to wish that there were a modern Romance language out there somewhere which had retained case inflections from Latin.
Then I found out about Romanian 
Yes, same here!
So, when native Spanish speakers emigrate to Brazil, do they end up assimilating pretty quickly due to the language similarities? This in turn, probably makes them use Portuguese with their family in the future than Spanish?
If they have motivation, go for it and talk with people for sure they will learn portuguese quite quickly. They’ll have problem with sounds in some words like :
ão - São Paulo, coração
ã - maracanã
po - poço, posso (this is really difficult for them)
But in the end, if they listen and try to speak they’ll get and will be more precise when they speak.
“This in turn, probably makes them use Portuguese with their family in the future than Spanish?”
This is something that I can’t say, because depends on a lot of things.
Paul from Langfocus posted a video about the differences between Spanish and Portugese a few minutes ago.
Did he read this thread or was it just coincidence?
“Did he read this thread or was it just coincidence?” Well probably coincidence but he has posted a few similar videos on romance languages and romance languages in general. I suppose the only thing that is missing is videos about Latin.
The Romance Languages and What Makes Them Amazing
The Portuguese Language and What Makes it Intriguing
The Spanish Language and What Makes it The Coolest
The Romanian language
The other how similar is … videos
So, are Brazilian Portuguese and Portugal Portuguese different languages? I am learning lessons from both of them on Lingq. I hope that doesn’t screw me up somehow.
They’re not different languages but I think it’s better to stick with one at first, especially for the listening/speaking part.
my god man how much language you are learning ha ha ha
all of them.
I don’t speak spanish, but I could talk with a lot of people in spanish just using the portuguese words in a way that I think it is in spanish. That’s portuñol.