hodor: oh, absolutely Howland is a fighter - as of the Rebellion. Though it's important to note that his skills, and the ones he teaches Meera, are emphatically
not tourney skills. Crannogmen fight on foot, in light armour, with frog-spear and net, not on horseback, in plate and mail, with lance, sword and shield. As the KotLT did.
A year or two prior, however, he is getting his backside kicked by these three squires. The same three squires Lyanna beats. (If Lyanna beating them is no big deal, then what does that say about Howland's
inability to beat them?)
Are you telling me it's credible that Howland, who is helpless to defend himself from being beaten up by these three squires, goes on to beat their masters: but totally
incredible that Lyanna, who easily beats the same three squires, could do it?