Have been doing 2 feet CO2 tank for about 2 years. Going to change my 2 feet to 3 feet soon.

I will be using the current Lapis Sand in my 2 feet, together with the mulm and whatever base fert that is left in the sand as the undergravel, add on JBL base fert and top off with new Lapis Sand.

I will use back the same filter for my 2 feet tank, Ehiem External Canister 2026 Pro II. Will wash the filter with the old tank water first.

Will use back about 70% of the plants from my 2 feet tank, the rest will be new plants. Critters will be the old tenants from my 2 feet. Later then add new tenants.

Will put back the critters to the 3 feet when the water had settled down after the setup. Will expect cloudy water for 1 day after setup due to bacteria bloom, but think the critters should be ok. They pull through when I re-scaped my tank on 2 occasions last time.

Do I start fertilizing the water column immediately after the setup? There will be a mixture of old plants and new plants.
Do I need to increase the lighting period slowly to 10 hours or can I start off with 10 hours straight away?
I think in short, do I need to acclimatise the plants first? As there will be old plants from my 2 feet, I'm a bit confused.