This two cards are usefull but not low mana cards.
If you play the earth splinter (otherwise you cannot use the Khmer Princess) and search for a low mana card in my opinion would be the Failed Summoner a good choice. For 2 Mana: 9 Life + Strenghen (so in the 10 Life) + Magic Reflect + Demoralisize this is a perfect card for 2nd position behind the tank and if you use the Khmer Princess you can even heal him with Triage.