Is secp160k1 with SHA-1 good enough for an altcoin?

I know that SHA-1 is broken. However, we still have hardened SHA-1, used for example in Git, and in many other places. And as far as I know, the 130-bit public key on secp256k1 is still not sweeped from the puzzle. Which means, that by starting with SHA-1 as a Hashcash function, and with secp160k1 implementation of P2PK on compressed keys, it should be good enough for fully functional altcoin, right?

Because I have some questions, and that kind of experiment should answer them:

1. How could Bitcoin look like, if it would be deployed earlier?
2. How to upgrade the chain, if secp256k1 or SHA-256 will be unsafe?
3. What is the real progress on breaking public keys? Are we really at 130-bit key now, or maybe the creator just moved the funds?

Also, I wonder, which curves below secp160k1 can be used, to reach similar properties, as in Bitcoin. Or: how to prove, that a given public key was created out of N-bit private key, without revealing it?

Another thing is using secq256k1, as a mirror to secp256k1, and create an altcoin, which would just collect proofs, that Bitcoin transactions are signed correctly, by using some kind of Zero Knowledge Proof. And I guess the same can be done with secq160k1, right?