Need some help routing waste pipes

[Leitnin]

Plumbing is being redone on a slab on grade single level home in Southern California.

I have a layout for bathroom 1 which as captioned below, looks like it is fine, only that the toilet drains into the line before the sink and shower. Is it worth it to avoid this? Anyone have an idea for a simple layout where the toilet drains last? I have about 20 inches of vertical space to work with.

As far as bathroom 2, I'm wondering if I can have the sink just drain into the main 4" stack above the toilet (red lines), or if I need to route it through the concrete via the green path and only vent it into the 4" stack.

On top of that, I have the tub drain and washing machine drain next to each other, and Im wondering if I can let the washing machine drain into the tub/shower stack without compromising it's vent. Ideally here would be a san-tee for the washer above the san tee for the tub/shower.

Any thoughts/help is greatly appreciated (link to the image below in case it's too small to read

https://imgur.com/a/LGGfJMg

)

 

[Leitnin]

So it has become clear that the washing machine (labeled as laundry drain in the images), should be a 2" drain and should be independent and drain into the main waste after the bathroom group. So that changes that plan pretty significantly.

The two questions that remain are:

1. In bathroom 1, should I rearrange everything to try to have the toilet the last fixture on the run (they will all enter the waste pipe close to each other regardless)

2. Can I drain the lav sink in bathroom 2 into the vent stack above the toilet drain?

Thanks

p.s. I just joined to post this but every time I have a plumbing question I see countless links to this forum, so although I am a new member, I have benefited from the advice here for a long time. I just saw the news about Terry and wish to offer my condolences and thanks not only to him but to everyone who supported him while he offered his knowledge to everyone around him.