What exactly costs 0.65BTC ~500US$??
A new code base and new wallet design shouldn't be so expensive??

Actually, that cost is in the ballpark.
http://thealtcoinguys.com/coin-packages/

As for the orphan issue? Maybe has to do with the stack amounts for staking?
I had them in stacks of 450 and got mucho orphans. Re-stacked into 900 stacks
and most of the orphans disappeared. So, I think it may have to do with the stacking
amounts, more than to do with wallet issues. 450 stacks worked fine up to the beginning
of the year. Probably more larger stacks competing against smaller ones.

Peace, Dennis