Dress for event 4-6 weeks after having a baby?

[toolonglurking]

Hi, I realise this isn't really an AIBU but I'm totally stuck.
I've got a very smart big family party where I'll be playing a pretty key part very soon after I'm due DC2.
The theme is 'touch of tartan' and I'm really struggling to find anything that would be suitable to wear.
I'm tall and about a size 18, but will also have all the extra tummy from pregnancy, and I'm dreading it. My very slim SIL will be there 3 months post birth and will no doubt be looking incredible.
Oh also hoping to breastfeed so that needs to be possible too.
I've looked at Seraphine, gap, new look, asos, and amazon (I can't get out to go shopping so it has to be bought online) Urgh I think I'll just have to wear my pj's!

Can anyone recommend anywhere I might be worth looking?

Could you get away with the tartan being a scarf or shawl?

A tartan shawl would be handy for breastfeeding too - could double up as a cover

Go for tartan shrug

How about something like this? It has straps with buttons. Nice shiny black top underneath and you could do a sort of one up/one down. Black tights and knee high boots?

www.bonprix.co.uk/products/maternity-tartan-dress/_/A-922118_8

Scarlett and Jo usually have some nice dresses. Second everyone else saying get a tartan shawl/scarf coming in handy for breastfeeding. Something like this would be ok for breastfeeding or they do separates if you prefer.

Tartan shawl, smart black maternity trousers and a smart top? Then if you have energy do nice hair and makeup and nobody will think anything is out of place.

I knew you lovely people would save the day - a shawl! Of course!
I'll get a nice simple, comfortable dress and a tartan shawl.
Thank you so much, I know it's not a big deal but it's been making me anxious!

Or an interpretation of tartan?

m.asos.com/asos-maternity/asos-maternity-nursing-check-shirt-dress-with-tie-front-detail/prd/8443683

Whatever you want to wear, then a comedy jock tartan hat with ginger hair tufts poking out.