You'll need to specify where you extracted misc_tables.vpp_pc to get proper strings, otherwise it'll give you numbers like you mentioned. Go ahead and extract misc_tables.vpp_pc first and put that folder into the same folder as ThomasJepp.SaintsRow.ExtractStrings.exe. Also put the hud_us.le_strings file you want to convert in the same folder. (This isn't necessary but makes typing in the command a bit simpler.)
Then in a command prompt, navigate to the folder you have ThomasJepp.SaintsRow.ExtractStrings.exe extracted to and your final command should look like this:
ThomasJepp.SaintsRow.ExtractStrings.exe hud_us.le_strings /xtbl:misc_tables.vpp_pc
You may need to change your folder name specified for the xtbl depending on if you renamed yours or anything. You'll now get a proper hud_us.txt file with names rather than numbers.
After that, it's really straightforward. You just follow the formatting of the other vanilla entries and add your homies wherever. I also recommend keeping both a vanilla copy of the hud_us.txt file and a copy of your modded one, because then you won't need to extract again if you change or add something to your mod. As for how to do it without renaming the driveup_homie, you need to add your homies to hud_us.txt based on whatever name you specify in the homies.xtbl in the <Display_Name> tag. Same for the <Display_Desc> tag. The <Name> tag should just be left as driveup_homie on any of your added homies. (This is so that your added homies are automatically unlocked as long as driveup_homie is.)
So in the hud_us.txt file, you could add, for example:
"HOMIES_ULTOR_BACKUP": "ULTOR BACKUP"
"HOMIES_ULTOR_BACKUP_DESC": "Get some backup from Ultor."
Then you just need to run the modified hud_us.txt file through ThomasJepp.SaintsRow.BuildStrings.exe and you're good to go.
(Forgive me if I forgot something, it's been a while and I typically do lol but that should work for you.)