You can configure IPv6 neighbor discovery (ND) attributes (MTU, M flag, O flag, and Prefixes) for each tenant network (ctag).
efa tenant epg create --name <epg-name> --tenant <tenant-name> 
     --ipv6-nd-mtu <ipv6-mtu> 
     --ipv6-nd-managed-config <true | false> 
     --ipv6-nd-other-config <true | false> 
     --ipv6-nd-prefix <ctag:list-of-prefix>
     --ipv6-nd-prefix-valid-lifetime <ctag,prefix:validTime>
     --ipv6-nd-prefix-preferred-lifetime <ctag,prefix:preferredTime>
     --ipv6-nd-prefix-no-advertise <ctag,prefix:noadvertiseflag>
     --ipv6-nd-prefix-config-type <ctag,prefix:configType(no-autoconfig| no-onlink | off-link)>
                efa tenant epg update --name <epg-name> --tenant <tenant-name> 
      --operation <ctag-range-add | vrf-add | anycast-ip-add> --ctag-range <ctag-range> --vrf <vrf-name>
      --anycast-ip <ctag:anycast-ip> --anycast-ipv6 <ctag:anycast-ipv6>
      --ipv6-nd-mtu <ipv6-mtu> 
      --ipv6-nd-managed-config <true | false> 
      --ipv6-nd-other-config <true | false> 
      --ipv6-nd-prefix <ctag:list-of-prefix>
      --ipv6-nd-prefix-valid-lifetime <ctag,prefix:validTime>
      --ipv6-nd-prefix-preferred-lifetime <ctag,prefix:preferredTime>
      --ipv6-nd-prefix-no-advertise <ctag,prefix:noadvertiseflag>
      --ipv6-nd-prefix-config-type <ctag,prefix:configType(no-autoconfig| no-onlink | off-link)>
                    The following example configures IPv6 Neighbor Discovery (ND) on a Tenant Network:
efa tenant show
+----------+---------+------------+-------------+-------------+-----------+-----------+----------------------+
|   Name   |  Type   | VLAN Range | L2VNI Range | L3VNI Range | VRF Count | Enable BD |        Ports         |
+----------+---------+------------+-------------+-------------+-----------+-----------+----------------------+
| vlanTen1 | private |   11-20    |             |             |    10     |   false   | 10.20.246.15[0/1-10] |
|          |         |            |             |             |           |           | 10.20.246.16[0/1-10] |
+----------+---------+------------+-------------+-------------+-----------+-----------+----------------------+
efa tenant vrf show
+---------+---------+-----------+-----------+-------------+-----+------+-------+------------------+------------+------------+
|  Name   | Tenant  |Routing    |Centralized| Redistribute| Max | Local| Enable|      State       |  Dev State |  App State |
|         |         |Type       |Routers    |             | Path| Asn  | GR    |                  |            |            |
+---------+---------+-----------+-----------+-------------+-----+------+-------+------------------+------------+------------+
|ten1vrf1 |vlanTen1 |distributed|           |  connected  | 8   |      | false |vrf-device-created| provisioned| cfg-in-sync|
+---------+---------+-----------+-----------+-------------+-----+------+-------+------------------+------------+------------+
efa tenant epg create --name ten1epg1 --tenant vlanTen1 --port 10.20.246.15[0/1],10.20.246.16[0/1] --switchport-mode trunk --ctag-range 11-13 
    --anycast-ip 11:10.0.11.1/24 --anycast-ip 12:10.0.12.1/24 --anycast-ip 13:10.0.13.1/24 
    --ipv6-nd-mtu 12:1600 --ipv6-nd-managed-config 12:true --ipv6-nd-other-config 12:true 
    --ipv6-nd-prefix 12:1:5::/64 --ipv6-nd-prefix-valid-lifetime 12,1:5::/64:2000 --ipv6-nd-prefix-preferred-lifetime 12,1:5::/64:2000 
    --ipv6-nd-prefix 12:1:6::/64 --ipv6-nd-prefix-valid-lifetime 12,1:6::/64:2001 --ipv6-nd-prefix-preferred-lifetime 12,1:6::/64:2001 
    --vrf ten1vrf1
efa tenant epg show
+---------+---------+----------+-------------------+---+------------+------------+------+---------+------+------+
|  Name   | Tenant  |   Type   |       Ports       |PO | SwitchPort | Native Vlan| Ctag |   Vrf   | L3Vni| State|
|         |         |          |                   |   |    Mode    |   Tagging  | Range|         |      |      |
+---------+---------+----------+-------------------+---+------------+------------+------+---------+------+------+
|ten1epg1 |vlanTen1 | extension| 10.20.246.15[0/1] |   |   trunk    |    false   | 11-13| ten1vrf1| 8192 |      |
|         |         |          | 10.20.246.16[0/1] |   |            |            |      |         |      |      |
+---------+---------+----------+-------------------+---+------------+------------+------+---------+------+------+
efa tenant epg show --detail
===========================================================================
Name          : ten1epg1
Tenant        : vlanTen1
Type          : extension
State         :
Description   :
Ports         : 10.20.246.15[0/1]
              : 10.20.246.16[0/1]
POs           :
Port Property : SwitchPort Mode     : trunk
              : Native Vlan Tagging : false
NW Policy     : Ctag Range          : 11-13
              : VRF                 : ten1vrf1
              : L3Vni               : 8192
+----+-------------+-----+----+------------+-------+----------------------+------+--------------+------------+-----------+-----------+
|Ctag|    Ctag     |L2Vni|BD  |Anycast IPv4|Anycast|      Local IP        |IPv6  |IPv6 ND       |  IPv6 ND   | Dev State | App State |
|    |Description  |     |Name|            |IPv6   |[Device-IP->Local-IP] |ND Mtu|Managed Config|Other Config|           |           |
+----+-------------+-----+----+------------+-------+----------------------+------+--------------+------------+-----------+-----------+
| 11 |Tenant L3    | 11  |    |10.0.11.1/24|       |                      |      |     false    |   false    |provisioned|cfg-in-sync|
|    |Extended VLAN|     |    |            |       |                      |      |              |            |           |           |
+----+-------------+-----+----+------------+-------+----------------------+------+--------------+------------+-----------+-----------+
| 12 | Tenant L3   | 12  |    |10.0.12.1/24|       |                      |1600  |     true     |   true     |provisioned|cfg-in-sync|
|    |Extended VLAN|     |    |            |       |                      |      |              |            |           |           |
+----+-------------------+----+------------+-------+----------------------+------+--------------+------------+-----------+-----------+
| 13 | Tenant L3   | 13  |    |10.0.13.1/24|       |                      |      |     false    |   false    |provisioned|cfg-in-sync|
|    |Extended VLAN|     |    |            |       |                      |      |              |            |           |           |
+----+-------------+-----+----+------------+-------+----------------------+------+--------------+------------+-----------+-----------+
Network Property [Flags : * - Native Vlan]
+-----+--------+----------+---------+----------+-------+
| Ctag| IPv6 ND| No       | Valid   | Preferred| Config|
|     | Prefix | Advertise| Lifetime| Lifetime | Type  |
+-----+--------+----------+---------+----------+-------+
|  12 |1:5::/64| false    |  2000   |  2000    |       |
+-----+--------+----------+---------+----------+-------+
|  12 |1:6::/64| false    |  2001   |  2001    |       |
+-----+--------+----------+---------+----------+-------+
IPv6 ND Prefix Flags
For 'unstable' entities, run 'efa tenant po/vrf show' for details
=================================================================