Well I mean, Id rather have Ambrose or whoever at 6 if it means that Fred and Jones will be part of the same attack. It does make the middle order slightly weak, but Flintoff at 7 and Broad at 8 would at least make the lower order somewhat competent.
Personally, unless we had another all rounder, I cannot see how having more batsmen who could bowl would make much of a difference. Collingwood is about as good of a bit part medium pacer as you are likely to get. I wish Vaughan would actually consider bowling a bit more because on the rare occasion, he has actually looked somewhat of a competent test match spin bowler. However, at the end of the day, you need 4 full time regular bowlers to take 20 wickets, and no just because Steve Waugh did it once or twice in the 90s doesn't mean it was anything other than stupid to go in with less. With Flintoff and Jones both injury prone and Panesar not good enough to be relied upon to bowl long spells when the conditions aren't in his favor (much in the same vein as Giles for he is troubled by batsmen that try to dominate him) it could leave England with a seriously disastrous situation if one or both of Jones and Flintoff breakdown.
Although your reasons for not being overly confident of picking Flintoff & Jones in a 4-man bowling attack is fair given their injury record. But if we are going to now pick them & yet have to unbalance the side with the thought at the back of our minds that they could break down any minute in a test match, well then why consider them at all regardless of their ability?
But given that ENG cannot forget such players, it is pretty much up to the physio/doctors etc to give the selectors the green light that these two slatwarts can last 5 days, since as i said it makes no sense picking them if they have the bodies of 70 year olds.
Once their fitness is claried then the best ENG XI for me would be:
Strauss
Cook
Vaughan
KP
Bell
Collingwood
Flintoff
Ambrose
Jones
Sidebottom/Hoggard
Panesar
Obviously some players have question marks over them or competition:
Strauss - needs to overcome to SA so as to convince all he is back.
Cook - although of late looks at bit sluggish & tentative at the crease would be backing him to come good, has the natural ability to do it IMHO
Bell - needs to take it to the next level pretty soon.
Ambrose - potentially has Prior (if his glovework improves) & Foster breathing down his neck if he lapses.
Sidebottom/Hoggard - well you would agree Hoggard hasn't really lost anything just was dropped foolishly in NZ (Anderson saving the selectors blushes with a good performance) & can't be recalled unless one of Broad/Anderson fails. So given that Freddie & Jones once fit are our two most reliable bowlers in most conditions we would only have room for one swing bowler so depending on who shows the best form will decide which of Sidebottom/Hoggard plays.