Hi I'm trying to create a new character in a training module, the idea is the following: a strong fighting-divine caster using magic for buffing more than healing, something competitive in a first line combat if properly buffed up (by himself

). So the choice is obviously a cleric but I never create such a character so I'm unsure about...all, precisely:
which abilities I should prefer (going only with Str&Con&Wis or taking also some Cha for domain abilities?)
which domain (maybe war and fire or war and strenght?)
features?
possibility to biclass with warpriest (is it a good idea or it's a loss of exp?), how many Cle lvls before biclassing?
Thanks in advance