The key like listed so many times above, and in so many past threads is patience. Don’t create a tank emergency over 1 occupant. You said your tanks still 4-5 mo old. That’s a little early for an anemone. You could have perfect numbers, but not have a tank environment established enough for long term success. Introduce in this order softies / LPS / SPS - Anemones. In any new build I do I wait patiently for my tank to let me know when it’s ready. When you see fewer and fewer algae outbreaks, along with your fist coralline algae bloom, you know your tanks on track. A mature tank just looks different, and shows it’s maturity. The trick is not over doing it.
I would go in this order.
Softies - 4-5 months before introduction
LPS - 6 - 8 months before introduction
Sps / anemones - 8 - 12 months
Buy a Duncan frag and a montipora frag. They are cheap and hardy, but also serve as great indicators of water quality for lps and sps. You start measuring success with them, then you know your tanks dialed in.