i believe goal number 1 should always be to protect yourself. reasonable expectations does this.
by your posts here, i think you're putting a lot of thought into this and i'm afraid you may need to keep it more light. dont put yourself into a position to undo everything you've done for yourself.
i think i would go with the light-hearted response, make a joke over his short responses (he did respond, so thats a plus) something like "well? good? i haven't seen you in x months and you give me well and good? well, i'm glad you're good, sincerely i am, and ..."
then i draw a blank, so something to keep the door open, if you feel coffee may be too pushy then something that may get him to text back and see where that leads.
what do you have to lose here? if this goes wrong, will you be hurt? if so then tread lightly. if not, then have fun with it. flirt a little.
i wouldnt wait 4 days to respond. to me, i dont always have my phone on, or in a meeting, or driving, but i usually respond almost immediately after seeing the text. so normal response time is hours or overnight.
"In a ham and eggs breakfast, the hen is involved, but the pig is committed".