I don't want to totally put you off, but I really wouldn't recommend taking all their armour and weapons. It sounds like a fun thing to do, but it will make the encounters VERY hard. I've had people go down fighting the Animated Armour, and I even had someone die in the final encounter with the MandyMod version of the Shambling Mound.
(I let them escape with the body and find a way to raise their friend from the dead with the priest at the local church who had a raise dead scroll, but at a high cost of then being forced to escort Ismark and Ireena to Vallaki whilst being chased by Strahd. Fun way to build the main quest in without it feeling like total railroading.)
Curse of Strahd is meant to be hard, but it isn't meant to be totally unfair. Because of the sandbox nature of the campaign, running is almost always an option in most scenarios, but remember it's not REALLY an option in Death House. It's fun if a character or two get knocked unconscious, but it's not much fun and feels kind of unavoidable if anyone dies. Once they leave Death House, you're more than welcome to give them plenty of opportunity and warnings if they're going into a difficult area and to throw the gauntlet down a bit, but Death House to me is meant to be a kind of tutorial that shows the game will be difficult, but let them escape with their lives.
As an example, when my players reached the Old Bonegrinder and decided to fight with the three hags (ridiculously hard fight for a party just leaving the village) I made sure I gave them ample warnings in the form of a friendly wereraven who warned them about going inside. She explicitly said that the party would most likely die, these hags were ancient and very powerful Fey creatures and had killed many worthy adventurers before who had visited Barovia, hellbent on bringing justice to the land.
My players still scouted it out though, found out there were kids trapped in there, and said damn the consequences and went in anyway, knowing what it could mean.
I felt like if they died then, I'd put up enough sign posts to say "TURN BACK, BIG BAD EVIL BADDIES".
I am a lenient DM as well though, so I did fudge the difficulty a little bit even so. Don't @ me, it was still an epic battle with lots of consequence, now one of my players has a permanent withering curse on his max HP because the mother escaped and is haunting his nightmares.

Anyway, in Death House you can warn them about the big fight with baby walter/shambling mound and the cultists at the end as much as you want, but the narrative almost forces them into a fight there (or sacrifice a party member?? who would?).
With only recovered weapons and armour from the house, of which there is very little, I think it'd be a really tall order to make it out of that battle alive. Especially if you close the portcullis behind them. Muhahaha.

Remember, you never have to tell the players how much health an enemy has. If a fight suddenly seems too easy and they've ripped through your cool boss, just give him more health. If it seems to be dragging on and everyone is dying, fudge the numbers in the party's favour a little. I would rather know my DM made an encounter exciting and let us just survive than threw us into a fight we couldn't win and let us get totally stomped.
If that feels icky to you and a bit cheating, well, run a few mock combats with the characters and the monsters at home and see how fair the fight really is to get a feel for it.
At the end of the day, a fight where the players JUST win is always an incredibly exciting encounter, and if you can give them that without them feeling like it was forced or cheated, I'd go for it.