DND 5E Dashing – Are There Any Consequences for Dashing Every Round?

Each combatant gets 1 action, a bonus action if they have a power to use it, a reaction and movement equal to their racial movement ability.

The rogue has way too many actions.

On action 1, do they have advantage or a buddy in melee? If so then they get SA. Action 2 if they have used SA, they don't get it again. Their bonus action is used to make this attack (see note below, this cannot be done with the longsword). Action 3 is impossible as they have no actions remaining. Action 4 is permissible, though it would provoke an opportunity attack. The rogue is left with some remaining movement but nothing else to do.

Also unless your rogue is human, and has taken a feat at L1, it cannot attack with TWF using a longsword. TWF requires light weapons be wielded in both hands.

So we have:

1. Action: attack
2. Bonus action: attack with off hand weapon
3. invalid, both bonus and regular action used.
4. Ok, but eats opportunity attack
5. invalid, both bonus and regular action used.

You don't need to decide on all of your movement in advance.

There is no "movement phase" in 5e. You can move, see what's around the corner, decide if you want to move further, and so on. You can attack, cast a spell, hide, or whatever else you selected as your action at any point during your turn, and you can move further afterwards. If your action includes multiple distinct activities (for example, multiple attacks), then you can separate them with movement.