Loras can offer strong female leadership. Hey, I mean from his grandmother! Come on people! Focus!
LOL....classic...... I have also thought Loras could be on his way to Dany. But, I hadn't compared the three men like that. Loras could be an ideal person to send (and I am sure he would not be alone). We can probably assume that the Tyrell's have knowledge of Dany's rising power, after all Mace was present at the small council when reports were given to Cersei about dragons. As well as the Golden Co. breaking its contract. If he went back and discussed it with his dear old mum it would make sense to not be wholly invested in only one side of a battle that may be coming.
Yes, the Tyrells appear to have made it to the top (Marg as queen). With that being said what would be the harm for house Tyrell sending someone to Dany just in case. Loras to represent the house in a disquise (murmer knight) along with someone else with more diplomatic skills. Thus they can find out her intentions. ie invasion or staying accross the narrow sea.
With Marg's imprisonment they may have been shocked into realizing what an incredible mess Cersei has made. And they may be regretting sending Loras who could bail her out in a trial. After this accusation even if Marg is acquitted there will always be lingering resentment with the current leadership of the church, which thanks to Cersei is a major power. If everything works out then great for the Tyrells, but they seem to be the kind of people that would not invest their entire future on a plan that seems to be falling apart at the seams.
If this happened I wonder who the knight is that was hurt? They could have just put someone in his armor and said go nuts, then after the battle if he was dead oh well, if he lived they just say he was hurt and sheild him from everyone not in the know, If he was truly hurt then oh well. Lets not forget the person that brought Cersei the news of Loras's injuries may not be loyal to her. Aurane Waters delivered Loras to Dragonstone, what if he was paid or promised land to return with dire news about Loras. After all when Cersei was arrested Aurane took off with her fleet. That does not speak well of his loyalty to her atleast
The Tyrells wanted power so they attached themselves to the Targ's,Then Renly, Then Lannister, now maybe Targ again. They are always with the rising star.