Looking at learning downwind this year and upwind/pack down/downwind is my best option logistically.

What wing has the best valve to stop water ingress and also comes with a bag that drains well so not too heavy on your back.

Also, what velcro straps do you use to attach the paddle?

Maybe not the answer you were looking for, but the Manera Offshore vest is really well thought out, and doubles for a bag by allowing to roll up and strap the wing to it. Also it has connection points for a paddle (on the back) although they recommend strapping the paddle onto the strut.

As for wing, I'd avoid those with a valve that requires internal pressure to seal and close completely. Ideally a valve with screw cap, or a spring to push + turn to deflate (sup valve?)

If you don't need to ride back upwind maybe one of those pocket kites people are playing with?

I'm a fan of the deflate downwinder. I use bicycle cargo straps to attach my paddle to the handles. Like these:

www.roswheel.com/collections/offroad-series/products/gear-straps

I have the blade pointed forward, I found this to be more balance and controlled than with blade pointed back.

I like a wing with dual inflation points. I feel it is easier and faster to dump the air and roll up the wing. BRM makes amazing wings:

boardridingmaui.com/wing.html

I use a 55L dry bag to stuff my wing into. My thought is that a mesh bag the will capture water in the wing when you fall that can't drain out and ends up being heavier on your back. Although, I have never tried a mesh bag, I might be wrong. This is what I end up with, I like that it has waist and chest straps to keep the bag snug when doing paddle ups

www.amazon.com/gp/product/B0B1Q7GTP8/ref=ppx_yo_dt_b_asin_title_o00_s02?ie=UTF8&th=1

I'm using a Smik V3 with aftermarket paddle strap handles from @zephyr.wing. Pack it into a roll top waterproof backpack.

Use a harness also if doing long runs upwind. I have found a 4m to be a good size for me.

Interesting points here! Makes me think that a hard handle wing will be harder to roll up .. needs more neatness! A soft handle wing would be preferred. Also less weight.

Baldy123: those straps allowing the paddle to double as handles look great. But what if you loose the paddle, let's say at the end of the upwind and preparing to deflate and downwind?

Makes me think of another question: do paddles need a wrist leash?

I've just gone through the same thought process. Decided to get a wing with sup valves for easy push button deflate and not leaving a big hole for water ingress - I went for a Flysurfer Tao but an F One should also work. Also a wing with no rigid bits so I can just smoosh it up and stuff into a dry bag without needing to be too particular with how I fold it ie no trailing edge battens or hard handles to worry about.
For strapping the paddle to the wing handles I just use lengths of Velcro One Wrap cut to length - sticks to itself , super useful. Hope this helps.

Yeah this is why we made the valves like we did as when I did a few pack up DW runs with our old wings I was always getting water in the bladder which sucked. New valves are so much better for this and just takes one problem away. I just strap a paddle to the hard handle and it's all easy to pack away. Just find a bag that drains very well and has plenty of straps so you can tie it nice and tight to your body to stop it swinging around. Oversized bad is good as well so it's easier to get in.

Here what the wing I use www.oneoceansportsaustralia.com/wind-wings-shop/p/one-v2-wind-wings-online-soon

Which has these valves

Manera (Fone) also make some straps for attaching a paddle to the side of the strut. Probably only works well with Fone wings though.

www.manera.com/en/products/waterwear/wing-paddle-attachment.html?color=1257

grunt straps from Bunnings will also do the job.

I don't like attaching paddle to handles, I've done this but annoys my grip and tires finger. when deflating and packing up sit on your paddle to stop it floating away.

There are these wings available somewhere.

2 (or 3) piece extending paddle might also be helpful for this application. Get the paddle as short as you can for the upwind to keep it out of the way and then extend to proper length on the downwind.

Any thoughts on small pumps? Types, models?

I don't know what is best, but this one pump inflation tube must be the worst. It deflates super slowly, pinches easily and just a complete PITA for deflating. Definitely prefer a strut valve.