For the moment, addressing the day to day chores, I am not a perfectionist so perhaps my way of doing things wouldn't suit.
Check the calendar before you go to bed, any appointments next day? Any bills need paying? Prescriptions re-ordering or collecting?
If it's run overnight, put any washing on, if not do it first thing after you get up and see to the DCs.
Allow yourself 'grooming time', grabbing a shower, or washing your hair, better still this can be pulling on something decent, (ie clean and fresh smelling).
Shop online, making sure you are in for the delivery slot. Encourage DH to add to a running shopping list of anything he uses up or that needs replenishing so you don't have to remember them all in your head and run out for things.
Use daily outdoor time for a walk to blow away the cobwebs or meet up with friends. Even if you can only manage a very short distance. Little ones like your company, they don't have to be constantly entertained, stimulation can be from 'helping' you or playing with their toys as you are in the same room but doing something else. Don't be embarrassed to plonk the older one down in front of the tv for a while, as long as you vet what they're watching.
When home, open windows, (cheaper than plug-in room fresheners), put on the radio, find some music. If you are a list person, write down 5 things to get done that day, no matter how trivial, to have the satisfaction of crossing them off.
My DM used to focus on one room a day over 5 days. I like to have one room straight where unexpected callers can sit without feeling they're in a muddle. I'd rather have company and "take me as you find me" than an immaculate home and nobody adult to talk to until DH returns.
I have heard someone suggest using a timer, coupled with a sort of 'chore and reward' programme. Set a timer for 20 - 30 minutes. I know some of that is taken up with nappy changing and kiddy interruptions.
So empty/load dishwasher or wash up, wipe all the kitchen surfaces, sweep up crumbs, empty bin, throw back the bedding to air beds, check bathroom(s). Then sit and rest, check MN, have a drink. 15 minutes' at least. Then walk round with something like a laundry basket, pick up stray stuff that belongs elsewhere or random papers, clothing, toys. When dusting cheat with a slightly damp cloth where appropriate, pick up dust rather than spread it. Then hoover and/or mop downstairs, then sit, rest, with drink and snack. Read DC1 a story, have 1:1 time when DC2 naps.
If you can have a restful soak in the bath while your parents/PILs are round, excellent. If someone can do some ironing or just fold up the bigger items, brilliant. If there are cobwebs to eradicate in the high corners or they can wash the downstairs windows, fantastic.
Ironing and cleaning windows imo are bonus items, you want to be able to walk through the house without tripping hazards, you want to eat without getting bugs, you want to have clean (if not perfectly ironed to Jeeves's standard) clothing.