please find below the answers to your questions:
1) Thinking about consulting. How would MBB of the world (London in particular) feel about getting post-mba friend with a year in ib experience (and a couple of closed deals) on board? Would they treat it friendly or wtf we need this lad? pre-mba experience is pretty general: some consulting/finance/generalist jobs from middle to no names.
If the IB name is good (GS, JPM, MS) your background would be solid for a switch to consulting; however there may be a challenge with the timeline for this year according to the office, as you would compete with MBAs for the position and target a post MBA position.
2) How would it get from work-life-balance perspective? 60-70 hours a week dont scare sh* of me - but 100 bites. Want to have development and also sort of human life.
You would for sure work less than IB – probably in the 60-80 hours range according to the project
3) Anyone would recommend a nice alternative? Heard PE is not an option for post-mba person and think it may be apple for apple. Corporate not sure will fit (any funky names like amazon could work?) - free to throw your view on here.
I am helping right now a post-MBA candidate switching from IB to PE (they ask cases there as well). PE hire post MBA, however you should have a strong IB background from a top name or top consulting experience or both.
Other alternatives really depend on your goal. Feel free to PM if needed for more info.
4) Last but upmost - dont want to stop developing and learning - need to hit that C-level suit one day.
Consulting would probably be the best shot for a C-role between the options you listed