Should I even bother trying to summon for Amelia or Tana?

I have those exact same units and 39 orbs, and I'm not summoning. I'm saving for the Christmas banner :)

If you don't need them it's better to wait and get a few more orbs for another banner imo.
I think we'll get a good banner in a couple of weeks from now, so save your orbs !

I got baited with 5 orbs ?, i had 113 orbs saved, now im down to 108 and christmas banner is coming im glad i didnt spend more to get amelia, i have one amelia was hoping to merge her.. lets hope theres no legendary heroes banner after christmas banner !

46 is a bit on the low side to guarantee you will get a 5*, but more importantly, do you need them? Amelia is good, but not better than hector, so i would only pull for her if you like her or something.
Tana is definitly better than valter, and by a long shot, but unless you want to make a flier emblem, or a mixed team that abuses guidance, maybe you can skip her?
I do like my tana a lot tho, so im not sure.

Honestly if you are F2P, 46 orbs is really risky.
I am always extremely unlucky, for instance I only got 2 units (and not those I wanted) on legendary banner with 250+orbs.
So I feel like 46 is very very risky, but it's up to you and how you feel your luck.