I have a 28 gallon tank that is happy and well established with 3 mollies, 4 platys, 9 rasboras, 1 flame GRAM,?

I have a 28 gallon tank that is happy and well established with 3 mollies, 4 platys, 9 rasboras, 1 flame gourami, 2 blue guppies, and 4 endlers, 1 zebra snail, 6 plants. I change about 10-25% of teh water every 4-5 days. So I have about 23 inches of fish doing well. Would like to add a tiny bit more, family says we want something blue. I am thing one of three options: 1 powder blue dwarf gourami (currently th efavourite choice in which case I would add another tall plant), 7 neon tetras, or 2 more fancy guppies. What do you think? Water is lovely and clear and always perfect for levels now. Currently a pretty happy set up with abut 5 inches to play with in terms fo the 1 inch per gallon rule.