hi. thanks for the feedback! we don't think there'll be a problem publishing on Steam. they don't have rules prohibiting similar app titles. our game and this interactive movie are pretty different and are difficult to confuse with each other. so there's very little chance it could lead to any legal problems. but an under-title idea might be interesting 😉
as for the launcher - this is the default way of installing almost every software (e.g. Discord).
moreover, you can change the installation folder. but, anyway, some data will still be put in appdata (like your profile data)
the antivirus is triggered because it's not an officially registered software. our game itself also sometimes gets flagged