Basement rough in advice

Hi all, We are adding a shower to where an existing bathroom was in the basement near the main stack. Planning to continue the new abs from the main stack towards the bathroom. I've drawn out my plumbing rough in plan. My concern is with that toilet being upstream from the shower I am not sure how to plumb it correctly. I'm thinking with a 4 x 2 wye and then loop back to the shower trap arm and p trap. The new vanity is going beside the toilet but I figure thats relatively straight forward 4 x 2 wye and then up through the wall and a p trap. There is an existing 2" copper vent that came down and acted as a wet vent for the old vanity. Planning to pick it up where it comes down through ceiling and then run it along the outside wall to vent the shower drain and sink. Any input is greatly appreciated. If it matters for codes I am in Ontario Canada.

Black specks in water?

Not sure if this is the right place to ask this, so I apologize if I'm a lost redditor rn. I work at a soda shop, and lately I've noticed black specks coming out of the water/lemonade nozzle on our soda machine. Occasionally I get them from our 7up Zero nozzle, as well. But no other soda dispenses them. We soak our nozzles in hot water every night, and we wash them by hand once a week. So I don't think dirty nozzles are the problem. Does anyone know what the black specks could be? I haven't found any concrete answers online yet. I even called our supplier, and they just said to make sure the nozzles are clean. Also, don't know if this is relevant, but I live in the middle of nowhere, and we get our water supply from a local underground well. It's not city water.

Not sure what to do here

At first I though this was super old wax right around the flange but upon trying to remove it I found it it’s actually metal which has been presumably hammered down. I think the previous toilet did not have a wax seal…. What should I do here? Jumbo wax and call it a day? Use an extender then wax it? The toilet flange is also metal. Building built in 1990; Thanks!

Sink draining slowly

This kitchen sink is draining slowly. Is this elbow to low? That thing sticking up in the back is a vent. This is a relatives house, they're elderly. I'm not handy and wonder if this needs a complete new setup. I want to know what I'm getting into before I call a plumber. Any help is appreciated, thanks!

My landlord locked our hot water

So my landlord installed this lock for the last tenants and can’t get it off anyone know what this is or any advice on how to get it off our plumbing in order to get our hot water back on?

Found out my sewage leads right out to the side of the house, sketchy family friend landlord said a contractor told him to dig a deep hole and fill it with rocks if he doesn’t want to connect it to the city sewage, I have to assume that’s illegal and the way it’s set up right is also illegal

Why does my bidet system add two water lines? I’m trying to exchange the one I inherited for a new one.

Faucet removal question

Complete novice here. My kitchen faucet broke and, this being the first time I've had such a situation, I decided to buy a replacement myself and see if I was up to the task of an installation. After disconnecting the lines and hose from the old faucet, the time came to remove the gasket on the old faucet and this plastic sheath made its presence known. For the life of me, I cannot figure out how to remove it. It seems completely stuck in place. Any advice about what it is and how I could be removed would be greatly appreciated.

What is this white hard puddy?

Whats the technical name of this.

I need to replace this but I can't find it online. Its attached to a spigot on a green roof.

What is this, and how do I get it to work normally?

Need to water our lawn. Just bought the house recently, and this faucet just trickles when I turn it. Why is it doing that? How can I get it to function normally?