Investing on Legendaries Hello,

I'm a F2P w/ VIP 10 half-way through to KvK 2.

I have a 5/5/2/2 YSG, a 5/1/1/1 Richard I, Exp. Æthel, (and... that's about it), other than that: a fresh Alex and Khan and I'm hoping to get enlisted in my kingdom's Constantine I MGEs.

I also know that YSG and Alex are already a given so, assuming I have them both, to whom should I head towards next? 

Thanks.