If all my topics that I've started are deleted. Do I still retain my rank ? Junior , Member , Senior etc... ? ?
If I decide to wipe my profile clean completely, will the rank stay ?

If you delete the post completely then your rank will definitely change to new. Actions I think are very necessary, now you have to wait for the time in the past for the action in the future.
But, (merit) will be in the right place. But I think it's better not to delete the posts completely.
No matter how many times you delete posts, they will still be there.
Here: