re: your guard list, I think you will really struggle with that build, you only have one fast formation (the Reg HQ) so grabbing objectives late in the game will be tough
with the rough riders, artillery batteries, sentinels and flak, you have 6 activations which are very vulnerable, 4 of them break as soon as they sustain a casualty....
you should really attach a hydra to every company you take, mostly to place the blast marker and prevent air assaulters gaining further advantage, but also to increase the ground flak you have, as you're not using planes either you are seriously lacking in air power, a marine air assault list would be thanking its lucky stars if it came up against that army
my suggestions would be to take at least another mechanised infantry company, that gives you two fast and robust formations to nab objectives with, drop the demolishers and add hydras to your companies, get rid of the shadowsword company and buy a pair of single tanks, if possible replace the basilisks with manticores, 9/10 times they are a better choice, and probably consider dropping down to two artillery batteries
I'd run with something like this:
RegHQ - Hydra
Mech inf -hydra
Tank Company - hydra
shadowsword
shadowsword
manticores
manticores
sentinels
rough riders
Thunderbolts
10 activations, respectable air cover with the planes, plenty of firepower and good engagement potential with the two mechanised infantry companies
optionally I'd swap the rough riders for a hydra battery to boost ground flak (people only make the mistake of letting rough riders survive once....) and potentially dropping a manticore battery to add-in deathstrikes if you're paranoid about titans and war engines making an appearance, use the sentinels to screen the artillery from teleporters, and try to be aggressive with the leman russes, make sure there is a commissar on the supreme commander stand (having a fearless supcom is worth the loss of a second leader in my experience) finally if you drop an artillery battery and the shadowswords, you can add in a pair of warhounds and second sentinel formation and you've got the all-conquering build used by Richard Laking to awesome effect over the last few years
