The vpxa is all you should need to start. Here are all the services for a 5.0 host:
PowerCLI R:\Server Systems\Software\Vmware\ESXi\ESXi 5.1 U1 w OM7.2> get-vmhostservice
Key Label Policy Running Required
--- ----- ------ ------- --------
DCUI Direct Console UI on True False
TSM ESXi Shell off False False
TSM-SSH SSH off True False
lbtd lbtd on True False
lsassd Local Security Authenticati... off False False
lwiod I/O Redirector (Active Dire... off False False
netlogond Network Login Server (Activ... off False False
ntpd NTP Daemon off False False
sfcbd-watchdog CIM Server on True False
vpxa vpxa on True False
You may have to manually connect them after restarting the services. You could try the below. May want to put a sleep in there to wait for services to restart though.
Get-Content VMHostNames.txt | %{
Get-VmHostService -VMHost $_ | ?{$_.key -eq ”vmware-vpxa“} | Restart-VMHostService
Set-VMHost -VMHost $_ -State "Connected"
}