Yes! You can use two 5-letter words in a single flower.
Though, they are synonymous, they do differ in spelling.
And quite interestingly, their third synonymous is their combination.
هيروق = ڤيكوق = هيروق-ڤيكوق
Happy Juggling = Selamat MenCuba
هيروق-ڤيكوق is "kata ganda" like- کوءيه-موءيه ,سايور-مايور ,ڬوتوڠ-رويوڠ - Normally this kata ganda must be present 2 words, if we want to make sentence. We cannot make sentences if we just using last word without their first pair word. For kata ganda هيروق-ڤيكوق, i never found the sentence that just using هيروق word only without 'his' pair ڤيكوق and otherwise. Are you sure i can use this word ( هيروق-ڤيكوق) for this contest?
Sorry if i ask a lot question.