Passport expiring for parents and new passport for new born

[Madhavan2015]

Requesting you to help me with my query. I have following situation.

1. We are on Tier-2 long term visa and in UK since Jan 2012. We need new passport for new born in UK. Birth registration already applied.
2. My passport is expiring in July 2015, want to renew.
3. My wife passport required change surname and passport expiring in August 2016, so want to renew.
4. How can we apply three applications(1 new passport for new born child in UK and 2 passport renewal of parents) at one go?
5. May I send application in one special delivery post, with all original and fees?
6. In March 2015 first week, we need to travel to India due to urgent family circumstances, so online appointment won't work as it is showing next appointment is on 02/02/2015. After baby's passport we have to apply for her visa, so need some time. I live in East Anglia 5-6 hours bus journey away from London.
7. How much time it will take to get three passports, if we apply three applications by post?
8. If won't renew my passport which is expiring in 6 months time, am I allowed to reenter UK within that time limit?

It is my humble request, please please kindly help me, I search all the places in https://www.hcilondon.in and on http://indiancitizenshiponline.nic.in/ but have no clear information on it.

Thanks in advance!