Adding PEX for New Bathroom

Hello all! I am adding a new basement bathroom and am getting close to running the plumbing. I have only ever worked with copper piping in my old house so I am a little lost on how to handle my PEX piping in my new house. I have a Pureflow ManaBloc, which I think has the compression attachments, so adding the new PEX pipe seems straight forward. However, I don't have enough hot or cold hookups. My other two bathrooms both have 3 colds (sink, toilet, shower) and 2 hots (sink and shower). My new bathroom will have tub/shower, sink, and toilet so I am planning on running the same amount of pipes. The problem is that I appear to only have 2 colds and 1 hot that are open, so I need to add one of each. I have attached pictures of the setup. The smaller manifold on the bottom right of the non-zoomed in image is for un-softened water so I don't believe that has any effect on what I am doing. It looks to me that the original plumber already added some sort of extension piece to the bottom of the Pureflow Manabloc to add two extra colds.

I am wondering:

1. Is it possible to add a hot and cold hookup to the current manifold with some sort of expansion. If not, what are my options for adding the new pipes?
2. The existing pipes are all 1/2". I assume I need to run 3 cold supplies and 2 hots because that is what the original plumber did. Is that what I should be doing? Or can I do 2 colds (one that would be for both the sink & toilet and one for shower) and 2 hots (shower, sink). If that is possible then I would only need to find a way to add one hot.
3. I am a little confused on how/why the left side of the bottom extension piece is cold when it is on the same side as all the hots. Is that truly cold?

Thanks!

 

I've never used a manifold like that specifically, but it does look like the cold side can be extended.

Typically, a 1/2" run is sufficient for a standard bathroom group. I wouldn't usually run 1/2" to each fixture, though there's nothing wrong with doing it that way.

If I was in your place, I would just take the spare hot/cold tap off the manifold and run to the new bath, then just branch off there with separate shutoffs at each fixture.

 

I like your idea of running just one hot and one cold supply line and branching it out in the bathroom, but is that an acceptable way to do it? This would make things so much easier for me since I already have an opening on the manifold for each but I also want to make sure I do things correctly.

 

It is both code compliant and commonly done.

Sometimes the home-runs to the manifold are preferred so there aren't any connections in the wall to ever leak. But PEX has become a well proven solution. Plus, the benefit of a single run of hot instead of multiple runs, is if you run the hot water in the sink, then get in teh shower, you don't have to wait for hot water to get to the shower also. The hot is already there and will get hot immediately. Water savings, etc.