Alright fluff is fun mate
So. Bigger assault squads is always fun, as 5 guys die pretty handily (and only get you the 1 special weapon...). Do you have a box of unbuilt DC? If so, I'd build them with bolters and 1 PF for counter-attacking/defending your back line, or for putting in a DP, or else with CC and grab them an assault vehicle (if you want, put them in the LR instead and DS termies, though this is risky and I normally wouldn't advise it). What do you mean by "buff the tacs?" If you mean make the noviate a priest, go for it but be warned that it's pretty expensive for a unit that won't be your opponents main focus. If you mean as a sergeant, go for it! If you mean something else, please explain... As for the "fluff" of honour guard squads. See, I don't really see them as fluffy unless they're alongside a captain. If it's a libby or chappie, I just don't see them being there. The whole point of them is kind of to defend the captain... IDK. Personally I would drop them, as I find they don't get much bang for their buck, but if you really want to use them then grab a captain and go for it! Thats a beast CC squad in the making (though, as mentioned, other units do it better for less).
I would not put 5 RAS in a rhino, but for an extra 5 points you get a gun that could make it worth it (it's not like you need the capacity). RAS in razorbacks is good - Rhinos, not so much unless it's 10 men and you really don't like JPs.
How I would run this: Drop Honor Guard and Chappie, buff the RAS to full, add some more DC (you could even keep the Chappie and add him here). Get them a transport. Lose the packs. Even a pod is better than packs for them... Remember: Assault vehicle, CC. Not, bolters. Anyway. Termies in LRC supported by jumpers, Pod comes down t1, Tac. take the backfield.
If you want ~130 point squads as filler, 5 RAS in a pod with a flamer and 2 HFs lays down 3 templates for 125. If you go higher, baals with ac/hb are almost always worth it. Even higher, you can get a fragioso in a pod for only 170.
If you're really adverse to pods (it doesn't fully fit into your whole fluff plan) then I'd advise either pretending the DC are RAS or dropping them...