When spells can be moved, must it be in a straight line?

Question

Healing Spirit (XGtE) says:

As a bonus action on your turn, you can move the Spirit up to 30 feet to a space you can see.

Moonbeam (PHB) says:

On each of your turns after you cast this spell, you can use an action to move the beam 60 feet in any direction

Can I move these spells to several points? For example, if my targets are arranged in a triangle formation, 10ft from each other, and my spell is currently on top of one of those targets, can I move the spell over all 3 of them before ending in a space?

On one hand, Moonbeam specifies direction, so it can be interpreted as just choosing a direction, and the spell only moves in that line. However, the spell also mentions any direction, so that can also be interpreted as moving any way you like.

Healing Spirit moves to a specific space. Can I choose the path the Spirit takes? Or can I only choose a single space as the destination, and the Spirit will take the shortest path there?

---

The reason I want to do this is that it would allow me to, for example, heal multiple targets with Healing Spirit.

whenever you or a creature you can see moves into the spirit's space for the first time on a turn or starts its turn there

And for the Moonbeam, I could damage multiple enemies.

When a creature enters the spell’s area for the first time on a turn or starts its turn there

The description does not say that the creatures has to move into the spirit's space on its turn, just a turn. I'm also assuming that moving the spirit on top of the creature would have the same effect.

Answer 1

Since you move the spell effect there is no reason why you cannot choose its path

There is no general rule that covers all spells whose AOE you can move. However, the two examples you specifically ask about can be addressed here sufficiently.

The description of the healing spirit spell (XGtE, p. 157) says:

you can move the spirit up to 30 feet to a space you can see.

This effect is very clear, you can move the effect 30 feet. It does not have to be in a straight line so, you can take any path you want.

The description of the moonbeam spell says:

you can [...] move the beam 60 feet in any direction

This one is perhaps a bit less clear, but a plain English reading would suggest that there is nothing restricting the movement path really. It doesn't say "any one direction" just "any direction".

This intent is confirmed in an unofficial tweet by rules designer Jeremy Crawford:

5e question: Moonbeam can be moved UP TO 60 ft. or EXACTLY 60 ft.? Other spells specify UP TO, Moonbeam doesn't

The intent is that you can move moonbeam's light up to 60 feet.

So again, you have complete control of the spell effect's path.

However, do note that this can be different depending on the wording of each spell. Some might restrict the path that can be moved even if these two don't. There is no general rule that covers all spells whose AOE you can move.

Moving an AOE that requires entering over a creature does not cause them to be affected by it

The Sage Advice Compendium has some explanation about AOE spells like moonbeam and how they affect enemies:

Our design intent for such spells is this: a creature enters the area of effect when the creature passes into it. Creating the area of effect on the creature or moving it onto the creature doesn't count. If the creature is still in the area at the start of its turn, it is subjected to the area’s effect.

And, stated another way by Jeremy Crawford on Twitter:

Movement of Moonbeam not count as creatures entering when spirit guardians moving into creature counts as entering?

Moonbeam, spirit guardians & the like work the same way: a creature, not the spell effect, does the entering.

So, no, no matter how you move the spells you cannot affect more creatures.