I would go with option #1, but I agree it's close with option #2. Between 1 and 2, it's really Refia vs. Chiz, CoD, and Cecil. Yes, Cecil is a top tier tank, and CoD and Chiz are both situationally very good units (CoD has lots of great support abilities and is a beast against humans, and Chiz can chain for big damage)... but Refia is a 5 star base and the best healer in the game right now. Because she is 5 star base, you are unlikely to pull her down the road unless you are whaling. You are, however, likely to pull some or all of Chiz, CoD, and Cecil, or similar units, over time.

Actually once Charlotte gets upgraded (assuming we follow Japan in this regard) she becomes a very valuable tank who can also serve as a mana battery. And When Rain gets his 6 star he becomes somewhat tanky too, in addition to full break. So you aren't totally without tank options.

Do you have any other decent units for #1? Putting both Rain and Ingus on the team is more full break than you need, so I'd leave Ingus on the sidelines at this point. Even if you don't have anything else decent right now, I suspect you will find another option in a week or two...

One argument on the flip side for #2 is that Chiz and Cecil both have very strong TMs. If you are planning on doing a lot of TM farming, it will be nice to have those. But honestly, by the time you are at a rank where you can TM farm somewhat profitably (e.g., 50+), you are likely to have more than 5 strong TMs in the queue... including possibly Cecil and/or Chiz...

The other thing to note is that Refia won't be the best healer forever. She will be very good for a long time, but once Tilith gets her 6 star form she will surpass Refia. Tilith is 4 star base, but not always available, but should be available again on a banner when she gets her 6 star upgrade.

All in all, pros and cons to both sides - fun one.