Use of LOL in response is to indicate laughing at someone, your intent may not be there but for most people it is used as a high level an insult.

Having used leash training on numerous cats, you don't get much benefit from using it inside other than to assess issues. It is a fight to get it on, get it off, they fight the leash and there is one way they can get out of it if they back up. You can assess this in one session inside. Next is an enclosed area outside the house, then a wide open area etc.

If you want to take a long slow process of whatever stage you are at now, that is fine. But if you want to at some time take the cat outside the real skill is when it is outside to be able reinforce what you want, and have the confidence to control the cat.