Yep, apparently the cravers do deplete the planets, but your main pop gain a plus 50% in food, science, industry and dust. So its very good in the short term, that is for sure.

Cravers are one of the best faction to splice. +5% on FIDS on pop with no depletion on horatio after splicing is considered great. Basically any industry or eventually food is great early. Also splicing Z'vali is also not recommended early due to fact that you need every pop possible early on home system to be considered equal with other players and they are rather easy to grow up since they are yours starting minor. Basically most of bonuses are rather good one way or another (maybe not manpower/ground dmg since 90% time there are far better bonuses to chose from), just adjust order in which you're splicing them since cost is getting higher and higher with every splice.

You can find all bonuses over here : Horatio Fandom

I see Basryxo are not included in the list but they are giving +3 industry.

I'm not sure about Xirmisala but i think their bonus is +1 industry, +1 dust.

For Kalmat i quite do believe its + 1 bandwidth.