This is possible if you prove to RIPE that the purpose of the network will be the same as before the purchase. Only the owners have changed. Not the official design of the network, according to the policy of RIPE, de makes you its owner.

Yes, but RIPE may ask why the changes have occurred. Perhaps, the legal and actual addresses have changed. In this case, you should notify RIPE that all customers and equipment have remained, and you will use the network the same way as before receiving it.

AG (Provider Aggregatable) are aggregated addresses of providers that are included in the LIR blocks and are aggregated into larger blocks.
IP addresses (Provider Independent) are part of the RIRs.

It can only be rented from LIR, or transferred from one LIR to another.

It is enough for the seller to give the password from the keys (MNT), and the Buyer to change them. Only there is a big risk that the Seller does not sell all of its networks and if the sold network gets into the SpamHaus list, the rest will also get there. And the Buyer runs the risk that the Seller has the right to request the password recovery from the RIPE network, as it is considered to be its legal owner.

No, AS can not be re-created separately from IP addresses. But you can request it via LIR from RIPE.

We are ready to provide this information to you personally, if such is the procedure prescribed in the contract of the transaction. Also you can address this issue to your LIR.

The entry of the network into the black list of the Internet does not affect end users. How to get out of this list, we can suggest a personal consultation.

We recommend using our help when choosing LIRa. We cooperate only with the personally verified LIRs. They correctly re-configure your block of IP-addresses and always help in the event of a problem. Entrust your objects to reliable LIRs.