Hello,
Your options at this point:
1/ convert area 50 stub into normal area->visit each SOHO box to change config
2/ use BGP overlay -> visit each SOHO box to change config
3/ on SRX 240 only, delete "no summaries" and inject the statics into area 50 as LSA-3 which is non-trivial/tricky but should be possible with another area+direct routes matching Your statics+FBF. Other people would call it horrible kludge 
My personal choice would be (2) as it would give a greater flexibility in the future.
HTH
Thx
Alex