The first five are correct. "small horses' names" should be "ainmneacha capall beag" (the adjective remains in the nom.sg. form when the gen.pl. of the noun is the same as the nom.sg., you got this right in the final sentence) "the small horses" = "na capaill bheaga" (you got this right two sentences earlier). "capaill" is slender, because the final consonant, "ll", is preceded by "i", this rule applies even to consonant clusters, the "i" makes the whole cluster slender: e.g. "iasc" - "sc" is broad; "éisc" - "sc" is slender ("na héisc bheaga"). Actually in Irish "ll" isn't considered a consonant cluster, it's a digraph (two letters representing a single phoneme or sound) and stands for a separate consonant distinct from that written with a single "l". You can tell if a noun is strong or weak by looking at how it forms the plural: If a noun adds any ending other than "-a" to form the plural, then it is strong (e.g. nouns forming the plural in "-anna", "-acha", "-í", "-ithe", "-ta", etc.); in strong nouns the plural is the same in all cases. If a noun forms the plural by slenderising (the final consonant), or by adding "-a", then it is weak; in weak nouns the genitive plural has the same form as the nominative singular. "Capall" forms its plural by slenderising, "capaill", so it is a weak noun, therefore the nominative plural will be "capall".