Hey man, thanks for popping in. All your stuff carries over to Shadow of the Erdtree, and you can freely move between there and the main game areas, using roundtable as the hub. I have not played it however.
I suspect the invasions you saw might have been NPC invaders, of which there are quite a few. If you've never invited another player for co-op, or invaded a player yourself, you are probably safe from player invasion. Varre's quest will open you up, but there's a solo alternative to completing his quest. That's how I've done it. I have all the messages and blood stains, but I've never been player invaded, and that was my aim. Don't care for that sort of thing. At first I didn't like the messages everywhere, and the stains. But now I see they aren't so bad. Some messages have proven very helpful "Look behind you" just in time, or "ambush ahead" and this sort of thing, proves helpful. And blood stains tell me there is danger afoot. But I get where you are coming from.
Have yet to go to farum azula. I beat Fire Giant and unlocked the forge grace, but then turned around to clean up stuff I've left behind.
To achieve anything in this game you must be prepared to dabble in the boundary of disaster — Stirling Moss
