Building a new race

So I was thinking of building --- actually adapting from the Fantastic Heroes and Witcher RPG the Tiefling to replace the Zaharan. What I'm not sure is would it be easier to just change out some racial abilities and use the Zhaharan or try and build a new one. Has anyone built a new race and how easy is it? The biggest thing I'd like to retain is the 3 random racial abilities that the Tiefling get. Basically I would remove the four Zhaharan abilities replace one with infravision and then the other three would be randomly determined from this table (duplicates are rerolled):

Table 1.5: Tieflings Special Abilities (roll a d100)

01-10: +2 bonus to saving throws and ½ dmg. vs acid

11-20: +2 bonus to saving throws and ½ dmg. vs cold

21-30: +2 bonus to saving throws and ½ dmg. vs electricity

31-40: +2 bonus to saving throws and ½ dmg. vs fire

41-50: +2 bonus to saving throws vs spells and magic effects

51-55: Immunity to poison and disease

56-60: Charm Person spell-like ability 1/day*

61-65: Darkness 15’ rad. spell-like ability 1/day*

66-70: Detect Thoughts (ESP) spell-like ability 1/day*

71-75: Detect Good/Evil spell-like ability 2/day*

76-80: Detect Magic spell-like ability 3/day*

81-85: Invisibility spell-like ability 2/week*

86-90: Vampiric Touch spell-like ability 1/week*

91-00: Choose any ability above

Axioms had rules for creating custom races, though I can't seem to find which issue they made it into.

I've used them to create the Goliath race, a race descended from humans who were crossbred with stone giants, and that has worked without issue so far.

Your idea of starting with Zaharan and replacing the specific powers gained should work without issue as well!

The rules for creating custom races hasn't reached Axioms yet! They're available only to Patrons at present.