For the phenomenon that the Squid web proxy does not start at boot time I am not alone: Forum topic1 (since 29 Mar core 155) and topic2 (since 29 May core 156).
I probably didn’t noticed this because my IPFire-server was never rebooted after the update to core 158 for 77 days. Don’t know why @ Neopegasus has a schedule reboot ones a week (maybe he thinks it is a good idea - but that’s only neccessary for a Windoof server 
)
Yesterday I started the web proxy manually via the web GUI. So this problem is solved for me.
Now there is still this ALSA startup failure. Maybe I just disable it completely.
Please: I wish that the web GUI gets an entry for ALSA on page Status->Services under ‘Addon - Services’ to do this as easily as for CUPS.