Eeep, wife bought betta for daughter. I have 0 knowledge.

Just yesterday, a small betta, now known as BabyB (BB), appeared in a 1 gallon bowl on my table. I am a saltwater/reef guy and have been for the past 7 years, so my general knowledge is good enough to keep it alive. What I'm looking for is advise on how to make this baby thrive.

Oh, I'm saying baby because it's so small. Even smaller than the ones I normally see in the cups at the LFS. About 1" from tailfin to mouth, and does not have dark coloring yet. Currently light pink, and you can see the organs inside.

I've been searching (google) writeups on betta care, and there's quite a few different information. So I want to ask the experts here instead (wish we had a how to sticky in here).

What is the minimum bowl size requirement that will keep this BB happy? I myself am not too happy about having BB taking up my space, but my daughter LOVES it and I will suck it up for my baby girl.

I can do water changes easily everyday, so would I need a filter?
And without a filter, is there a cleanup creature, such as a shrimp or fish or snail, that you recommend to house in there to pick up the leftovers?

Do bettas jump? Should I cover the bowl?

Lights required? Currently set up in a room that gets lots of sunlight, so very bright.

There's some bamboo that was thrown in the bowl.

I'm currently going through the other threads to learn more, so sorry if I ask repeat questions. I would be greatful of any other info you deem important.

Just read on another thread about not using RO water, so I'm going to begin a slow tap water change with declor water.

Also curious about stress lines indicated in the other thread. Please respond here or there, I will read it =)

Starting to love BB. She's reminding me of my tomato clown I had a few years ago. She was just "sitting" when I came into the room. Once she noticed me, she was swimming towards me, and followed me around the room. Gives me the impression of a wet dog.

Going to have to hit the store later. What temp should it be set at?

Not sure if you could tell from pictures, but her colors have definately gotten darker since day 1.